Bone Histology Research Articles

Magnesium Membrane Shield Technique for Alveolar Ridge Preservation: Step-by-Step Representative Case Report of Buccal Bone Wall Dehiscence with Clinical and Histological Evaluations

Background/Objectives: Despite the increased use of new resorbable magnesium membranes, there are no reported cases or studies on the use of resorbable magnesium membranes in combination with bone grafts for alveolar ridge preservation (ARP) in cases with severe buccal bone wall dehiscence. This case report aimed to evaluate the effectiveness of the magnesium membrane shield technique in conjunction with bone grafting for ARP, assessing both clinical outcomes and histological bone regeneration. Methods: A 44-year-old female patient presented with a vertical fracture on tooth 24 (FDI Notation System) accompanied with complete destruction of the buccal bone wall. The treatment plan included tooth extraction, ARP using a combination of anorganic bovine bone and autologous bone grafting, and the application of a magnesium membrane as a shield to the pre-existing buccal wall. Six months post-procedure, a bone biopsy was taken from the implant site using a trephine bur. Results: Clinical and radiological evaluations six months after the procedure demonstrated sufficient bone volume for implant placement. Additionally, in the next three months, soft tissue conditioning with a provisional crown resulted in an aesthetically and functionally satisfactory outcome. Histological analysis of the bone biopsy revealed well-formed new bone in direct contact with residual biomaterial, with no signs of inflammation. Osteocytes were clearly visible within the newly formed bone matrix, indicating successful bone maturation. Active osteoblasts were observed along the bone-biomaterial interface, suggesting ongoing bone remodeling and integration. Additionally, histomorphometric evaluation revealed 47% newly formed bone, 32% soft tissue, and 19% residual biomaterial. Conclusions: This case demonstrates the potential of the magnesium shield technique as an ARP technique in cases with severe buccal wall dehiscence. The technique yielded satisfactory clinical outcomes and promoted successful bone regeneration, as confirmed by histological analysis.

Histomorphometric Analysis of Osseointegrated Intraosseous Dental Implants Using Undecalcified Specimens: A Scoping Review

Bone histology and histomorphometry are reliable diagnostic tools for the assessment of the bone–implant interface, material safety and biocompatibility, and tissue response. They allow for the qualitative and quantitative analysis of undecalcified bone specimens. This scoping review aims to identify the most common staining techniques, study models for in vivo experiments, and histomorphometric parameters used for quantitative bone evaluation of osseointegrated dental implants in the last decade. The Web of Science, PubMed, and Scopus databases were searched on 1 July 2024 for relevant articles in English, published in the last ten years, and the data were exported to an MS Excel spreadsheet. A total of 115 studies met the eligibility criteria and were included in the present review. The results indicate that the most common study models are dogs, rabbits, and pigs. Some of the most frequently used methods for the assessment of the bone–implant interface are the Toluidine blue, Stevenel’s blue with Van Gieson, and Levai–Laczko stainings. The results from this study demonstrate that the most commonly used histomorphometric parameters in implant dentistry are the bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), bone area (BA), and bone density (BD). This review presents the recent trends in histomorphometric analysis of dental implants and identifies some research gaps that necessitate further research.

Osteogenic effect of alogliptin in chemical-induced bone loss: a tri-modal in silico, in vitro, and in vivo analysis.

To investigate the effects of Alogliptin in chemical-induced post-menopausal osteoporosis. The binding affinity of alogliptin with osteogenic proteins was analysed in silico. The effect of alogliptin on osteogenic proteins and mineralization of osteoblastic cells was evaluated in UMR-106 cells. Further, in vivo anti-osteoporotic activity of alogliptin was evaluated in postmenopausal osteoporosis. Various bone turnover markers were assayed in serum. This followed the analysis of microarchitecture of bone, histology, and immunohistochemistry (IHC) of bone tissue. Docking scores showed that alogliptin has binding affinity for bone alkaline phosphatase (BALP), osteocalcin, and bone morphogenic protein (BMP-2). Alogliptin also enhanced mineralization of osteoblast cells, evidenced with increased ALP, osteocalcin, and BMP-2. Animal studies revealed significant elevation of bone formation markers, bone ALP, osteocalcin and BMP-2, and decreased bone resorption markers, receptor activator of NF-κβ (RANKL), cathepsin K (CTSK), tartrate resistant acid phosphatase (TRAcP5b) in VCD-induced post-menopausal osteoporosis. Micro computed tomography (μCT) analysis and histology of femur bone and lumbar vertebrae demonstrated decrease in trabecular separation and improved bone density. IHC of femur showed reduced DPP4 enzyme. Alogliptin increased mineralization in osteoblast cells. It had beneficial effects also altered bone turnover markers, repaired the trabecular microstructure, improved bone mineral density, and exhibited bone forming capacity targeting DPP-4 enzyme in postmenopausal osteoporosis.

Modified laminar bone did not stop sauropods from achieving large body sizes

ABSTRACT An almost complete dinosaur femur found in the Baynshire Formation (late Cenomanian to Santonian; Mongolia) in 1963 during the Polish–Mongolian Paleontological Expeditions is described here for the first time. The morphology of the femur and bone histology suggest that the specimen was a representative of the Titanosauriformes, the predominant sauropod clade during the Cretaceous. Bone tissue exclusive to this clade, modified laminar bone that indicates a reduced growth rate, is identified in the thin sections taken from the femur. Based on its bone histology, the already ca. 20-meter-long specimen appears to be a subadult. This specimen achieved a significantly larger size compared with other Titanosauriformes with modified lamellar bone at a similar growth stage.

METTL14-mediated HOXA5 m6A modification alleviates osteoporosis via promoting WNK1 transcription to suppress NLRP3-dependent macrophage pyroptosis

BackgroundOsteoporosis is a commonly diagnosed metabolic bone disease. NLRP3 inflammasome activation and pyroptosis are observed during osteoporosis. However, the mechanism by which NLRP3-mediated pyroptosis contributes to osteoporosis remains largely undefined. MethodsOvariectomized (OVX) mice were employed as an in vivo model of osteoclastogenesis. H&E staining and micro-CT detected the histological changes and bone parameters in the femur tissues. RANKL-treated macrophages were used as the in vitro model of osteoclastogenesis, and LPS/ATP treatment was used as the macrophage pyroptosis model. The cytotoxicity, cytokine secretion and caspase-1 activity were assessed by LDH release assay, ELISA and flow cytometry, respectively. The osteoclast formation ability was detected by TRAP staining. qRT-PCR, IHC and Western blotting detected the expression and localization of METTL14, pyroptosis-related or osteoclast-specific molecules in femur tissues or macrophages. Mechanistically, MeRIP assessed the m6A modification of HOXA5. Luciferase and ChIP assays were employed to detect the direct association between HOXA5 and WNK1 promoter in macrophages. ResultsMETTL14, HOXA5 and WNK1 were decreased in OVX mice, which was associated with pyroptosis. METTL14 or HOXA5 overexpression suppressed macrophage-osteoclast differentiation and pyroptosis, along with the upregulation of WNK1. METTL14-mediated m6A modification stabilized HOXA5 mRNA and increased its expression, and HOXA5 regulated WNK1 expression via direct binding to its promoter. Functional studies showed that WNK1 knockdown counteracted METTL14- or HOXA5-suppressed pyroptosis and macrophage-osteoclast differentiation. In OVX mice, overexpression of METTL14 or HOXA5 alleviated osteoporosis via suppressing WNK1-dependent NLRP3 signaling. ConclusionMETTL14-mediated HOXA5 m6A modification increased its expression, thereby inducing WNK1 expression and suppressing NLRP3-dependent pyroptosis to alleviate osteoporosis. The combination of METTL14 or HOXA5 agonist with pyroptosis targeted therapy may be a promising therapeutic approach for osteoporosis. The Translational Potential of this Article·•METTL14 or HOXA5 overexpression suppressed macrophage-osteoclast differentiation and pyroptosis in macrophages.·•METTL14-mediated m6A modification stabilized HOXA5 mRNA and increased its expression.•HOXA5 regulated WNK1 expression via direct binding to its promoter.•Silencing of WNK1 reversed METTL14- or HOXA5-suppressed pyroptosis and macrophageosteoclast differentiation.·•METTL14 or HOXA5 overexpression alleviated osteoporosis via suppressing WNK1-dependent NLRP3 signaling in OVX mice.

Effect of Huoxue Jiegu compound capsule on osteoblast differentiation and fracture healing by regulating the PI3K/Akt/mTOR signaling pathway in rabbits

ObjectiveTo examine and talk about the mechanism of the Huoxue Jiegu compound capsule's effects on osteoblasts and the PI3K/Akt/mTOR signal pathway in rabbits suffering from tibial fractures. MethodIn vitro, CCK8 was used to assess the survival rates. Alizarinred staining was used to evaluate mineralized nodules. ALP staining was used to observe the osteoblasts. qRT-PCR was used to determine the mRNA expression of the bone formation-related factors BMP-2, bFGF, and TGF-β. In vivo, three groups of nine male rabbits each were randomly assigned to three groups: the Model group, the Huoxue Jiegu compound capsule group (HXJGC group), and the inhibitor group (HXJGC+3-MA), four weeks following the intervention. HE staining was employed to examine the rabbits' bone histology. immunohistochemistry was employed to examine the relative expression of the proteins VEGF and LC3-II. Western Blot was utilized to examine the relative expression of the proteins Beclin-1, LC3-II/Ⅰ, p62, p-PI3K, p-AKT, and p-mTOR. ResultsCompared to the control group, the medium- and high-dose groups exhibited considerably higher survival rates (P < 0.05), as well as enhanced cell proliferation and differentiation (P < 0.05) and more pronounced mineralized nodules. (P < 0.05), but the low-dose groups showed no appreciable variation. In the low, medium, and high-dose groups, there was a substantial reduction in the expression of bFGF mRNA, whereas the levels of BMP-2 and TGF-β mRNA were considerably higher than in the control group (P < 0.05). In vivo, after four weeks of treatment, the model control group and inhibito group had a large amount of fibrous hyperplasia accompanied by bleeding and a small amount of inflammatory cell infiltration. But in the HXJGC group, new cartilage appeared, and the surface of the cartilage was smooth and flat. Beclin-1 and LC3-II/I expression in the HXJGC+3 MA group was significantly lower than in the HXJGC and Model groups (P < 0.05). The HXJGC group showed lower p62 expression than the HXJGC+3 MA and model groups (P < 0.05). The HXJGC group exhibited significantly reduced levels of p-PI3K, p-AKT, and p-mTOR expression in comparison to HXJGC+3 MA groups (P < 0.05). ConclusionRabbits with tibial fractures can be treated with HXJGC, which can control the expression of the PI3K/Akt/mTOR signal pathway. It can promote the differentiation and maturation of osteoblasts at the fracture end of rabbits, accelerate the recovery of fractures, and achieve the purpose of treating the disease.

Growth and life history of freshwater chelydrid turtles (Testudines: Cryptodira): A bone histological approach.

The current study examines the growth pattern and lifestyle habits of the freshwater snapping turtles Chelydra and Macrochelys based on limb bone histology. Femora, humeri, and tibiae of 25 individuals selected from a range of ontogenetic stages were assessed to determine inter-element and intraskeletal histological variation. Osteohistological assessment of multiple elements is consistent with overall moderate growth rates as revealed by the dominance of parallel-fibered bone. However, the growth was cyclical as shown by deposition of multiple lines of arrested growths in the compacta. It appears that the bone tissue of C. serpentina is more variable through ontogeny with intermittent higher growth rates. M. temminckii appears to grow more slowly than C. serpentina possessing compact and thick cortices in accordance with their larger size. Overall, vascularization decreases through ontogeny with humeri and femora being well-vascularized in both species. Contrarily, epipodials are poorly vascularized, though simple longitudinal and radial canals are present, suggesting differences in growth patterns when compared with associated diaphyseal sections. The tibiae were found to be the least remodeled of the limb bones and therefore better suited for skeletochronology for snapping turtles. Intra-elementally, femora and humeri preserved higher cortical vascularity ventrally, suggestive of faster relative growth. We hypothesize that the differential growth pattern in limb bones of snapping turtles may relate to differential functional constraints, where forelimbs are operational in swimming while the hindlimbs provide stability.

Skin Anatomy, Bone Histology and Taphonomy of a Toarcian (Lower Jurassic) Ichthyosaur (Reptilia: Ichthyopterygia) from Luxembourg, with Implications for Paleobiology

A partial ichthyosaur skeleton from the Toarcian (Lower Jurassic) bituminous shales of the ‘Schistes Carton’ unit of southern Luxembourg is described and illustrated. In addition, associated remnant soft tissues are analyzed using a combination of imaging and molecular techniques. The fossil (MNHNL TV344) comprises scattered appendicular elements, together with a consecutive series of semi-articulated vertebrae surrounded by extensive soft-tissue remains. We conclude that TV344 represents a skeletally immature individual (possibly of the genus Stenopterygius) and that the soft parts primarily consist of fossilized skin, including the epidermis (with embedded melanophore pigment cells and melanosome organelles) and dermis. Ground sections of dorsal ribs display cortical microstructures reminiscent of lines of arrested growth (LAGs), providing an opportunity for a tentative age determination of the animal at the time of death (&gt;3 years). It is further inferred that the exceptional preservation of TV344 was facilitated by seafloor dysoxia/anoxia with periodical intervals of oxygenation, which triggered phosphatization and the subsequent formation of a carbonate concretion.

A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan

Abstract Recent fieldwork in the late Middle Jurassic Balabansai Formation of Kyrgyzstan has yielded a partial skeleton of a large theropod dinosaur. The material includes a few bones of the skull (postorbital, quadratojugal), dorsal and sacral vertebrae, fragments of the pectoral girdle and forelimbs, and an almost complete pelvic girdle and hindlimbs, and is here made the type of a new theropod taxon, Alpkarakush kyrgyzicus gen. et sp. nov. Alpkarakush can be diagnosed by an extremely developed orbital brow on the postorbital, a pneumatic opening leading into cavities in the neural arch from the centroprezygodiapophyseal fossa in the posterior dorsal vertebrae, an almost enclosed ventral sulcus in manual phalanx II-1, a narrow and deep intercondylar groove on the anterior side of the distal femur, and an epicondylar crest on the distal femur that is offset from the distal end. A second, fragmentary, and smaller specimen from the same site represents the same taxon. Based on long bone histology, the type of Alpkarakush represents a late subadult individual, whereas the smaller specimen is a juvenile, possibly indicating gregarious behaviour. Phylogenetic analysis places Alpkarakush in the Metriacanthosauridae, underlining the diversity and wide distribution of this clade in the Jurassic of Asia.

Preventing bisphosphonate induced osteonecrosis of the jaw with a polyguanidine conjugate (GuaDex): A promising new approach

Osteonecrosis of the jaw (ONJ) is a relatively rare side effect after prolonged use of bisphosphonates, which are drugs used to treat bone resorption in osteoporosis and certain cancers. This study introduces a novel ONJ model in rats by combining exposure to bisphosphonates, oral surgery, and bacterial inoculation. Potential ONJ preventive effects of polyguanidine (GuaDex) or antibiotics were evaluated.The study consisted of twenty-four male Wistar rats were divided into four groups. Groups 1 to 3 were given weekly doses of i.v. Zoledronic acid (ZA), four weeks before and two weeks after an osteotomy procedure on their left mandibular first molar. Group 4 was a negative control. Streptococcus gordonii bacteria were introduced into the osteotomy pulp chamber and via the food for seven days. On day eight, the rats were given different treatments. Group 1 was given a GuaDex injection into the osteotomy socket, Group 2 was given an intramuscular (i.m.) injection of clindamycin, Group 3 (positive control) was given an i.m. injection of saline, and Group 4 was given an i.m. injection of saline. Blood samples were taken two weeks after the osteotomy procedure, after which the rats were euthanized. Bone healing, bone mineral density, histology, and blood status were analyzed.The results showed that Group 1 (GuaDex) had no ONJ, extensive ongoing bone regeneration, active healing activity, vascularization, and no presence of bacteria. Group 2 (clindamycin) showed early stages of ONJ, avascular areas, and bacteria. Group 3 showed stages of ONJ, inflammatory infiltrates, defective healing, and bacterial presence, and Group 4 had normal healing activity and no bacterial presence.Conclusion: ZA treatment and bacterial inoculation after tooth extraction inhibited bone remodeling/healing and induced ONJ characteristic lesions in the rats. Only GuaDex apparently prevented ONJ development, stimulated bone remodeling, and provided an antimicrobial effect.

Prognostic factors and impact of bone invasion in T1/2 size (

The aim of this study was to characterize the clinicopathological features and prognostic factors of T1/2 size (<4 cm) gingival squamous cell carcinoma (SCC) and to verify the impact of bone invasion. This was a single-centre, retrospective cohort study involving 206 patients with gingival SCC (maxilla or mandible), treated between 2000 and 2020. The patients were divided into three subgroups based on tumour size and bone invasion. The 5-year overall survival (OS) and disease-free survival (DFS) were 80.6% and 67.6%, respectively. Histological differentiation, advanced T stage, positive resection margin, bone invasion, and postoperative adjuvant therapy were associated with a poor prognosis (P < 0.05). Multivariate Cox analysis indicated that only histological differentiation (hazard ratio (HR) 2.68, P = 0.007) and bone invasion (HR 2.08, P = 0.036) were significantly associated with DFS. Bone invasion was observed in 145 (70.4%) patients, of whom 43 (20.9%) had a T1/2 size tumour. The subgroup with bone invasion and T1/2 size showed significantly worse OS and DFS when compared to the subgroup without bone invasion and similar or worse survival when compared to the subgroup with bone invasion and T3/T4 size. Histological differentiation and bone invasion were poor prognostic factors for gingival SCC, even in cases with small-sized tumours. For suspected bone invasion in small-sized tumours, an adequate bone margin is necessary and postoperative adjunctive therapy needs to be considered.

Effect of training on bone quality in rats with insulin resistance induce by fluoride consumption.

When large amounts of Fluoride are consumed produces insulin resistance, but exercise can reverse insulin resistance in rats, because of a high fluoride uptake by bone tissue. However, bone quality has not been studied in those experiments. Therefore, the aim of this work was to evaluate bone quality in rats treated with fluoride when performing exercise. Sprague-Dawley rats were divided into 3 groups (n=6 per group): Control (drinking water without fluoride), Fluoride (drinking water with fluoride 15 mg/L for 30 days) and Exercise (daily running on a treadmill and drinking water with fluoride 15 mg/L for 30 days). Then, bone mineral density, mechanical and histological properties and bone fluoride level were measured. No effect of treatment on any bone parameters were observed. These results indicate that exercise normalizes glucose metabolism in insulin-resistant rats by bone fluoride uptake; however, this increase in bone fluoride does not manifest in bone deterioration.

#1648 Chronic kidney disease-mineral bone disorder and fractures in predialysis patients

Abstract Background and Aims Chronic Kidney Disease (CKD) patients have a complex physiopathology of bone fragility given the development of mineral bone disorder (CKD-MBD) and are at increased fracture risk [1]. Bone turnover, mineralization, and volume (TMV) classification, as proposed by Kidney Disease Improving Global Outcomes (KDIGO), defines different subtypes of renal osteodystrophy (ROD), and is evaluated through bone biopsies and respective histomorphometric analysis. The impact of these parameters and of different ROD subtypes in fracture occurrence has not been evaluated. We aim to evaluate the incidence of fractures in patients with predialysis CKD and the relationship of ROD subtypes and the impact of bone volume with the occurrence of fractures. Method We conducted a retrospective study that enrolled 54 patients (40-89 years old) followed in a predialysis clinic between 2014-2023. Blood tests, bone biopsies and histomorphometric analysis were performed at the beginning of follow-up. Data from dual x-ray absorptiometry (DXA) scan were collected if available. Information regarding clinical evident fractures was recorded from analysis of clinical registries. Radiographies of the thoracic and/or lumbar spine were evaluated to detect asymptomatic vertebral fractures. Results Median follow-up time was 7.5 ± 3 years. Mean age at the time of bone biopsy was 65.4 ± 9.8 years old and most patients were male (n = 43, 79.6%). The majority had CKD stage 4 (53.7%). During follow-up, 20 (37%) patients progressed to kidney replacement therapy and 5 (9.3%) died. DXA scan was performed in 19 patients (35.2%). Of these, 5 had osteoporosis (T-score ≤-2,5). The histomorphometric analysis showed that 40.7% (n = 22) patients had normal bone histology, 37% (n = 20) low bone turnover with normal mineralization (adynamic bone disease) and 22.3% (n = 12) high bone turnover with normal mineralization (hyperparathyroid bone disease). Two patients sustained clinical evident fractures. Radiographies of 51 patients were reviewed and asymptomatic vertebral fractures were identified in 3 (5.9%). The group that suffered fractures had higher phosphorus levels and these differences were statistically significant (4.1 mg/dL vs 3.5 mg/dL, p = 0.047). None of the patients with osteoporosis diagnosed by DXA scan fractured and bone mineral density (BMD) by DXA was similar between the groups (−1.05 vs −1.04, p = 0.530). The different histomorphometric subtypes and circulating biomarkers did not correlate with the incidence of fractures. Patients with fractures had more frequently low bone volume (40%) than patients who do not sustained fractures (25.5%) but this difference was not significant (p = 0.579). BV/TV was lower in the group that sustained fractures during follow-up (16.1 (11.9-17.2) vs 19.0 (16.2-23.6)) and this achieved borderline significance (p = 0.052). Femoral neck BMD measures in the patients who had an available DXA scan did not show any correlation with BV/TV (r = 0.039, p = 0.874). Conclusion No relationship was found between different ROD subtypes and the incidence of fractures. However, when considering bone volume isolated (but not BMD assessed by DXA), a marginally significant association was found between a low BV/TV value and the occurrence of fractures. High phosphorus levels also associated with fractures and have been previously described as a possible risk factor for fractures not only in CKD patients but also general population [2, 3]. Further studies with a larger population are needed to validate these conclusions with statistical power.

Optimization of Formic Acid-Formalin-Based Decalcification Protocol for Rat Calvarial Bone Histology

Decalcification is crucial in histological processing, particularly for studying mineralized tissues like bone. The choice of decalcification method can significantly impact the quality of histological sections and the preservation of tissue morphology. This study aims to establish a standardized protocol for decalcifying rat calvarial bone using a formic acid-formalin-based decalcification solution. The protocol was systematically optimized and evaluated based on various parameters, including decalcification time, formic acid concentration, and tissue integrity preservation. The decalcification process was evaluated through comprehensive assessments, including gross physical examination, chemical analysis, and radiographic imaging techniques. Our result demonstrated that the 10% formic acid concentration proved most effective for decalcifying rat calvarial bone samples within eight days, excelling in mineral content removal while preserving specimen structural integrity. In contrast, the 5% concentration failed to complete decalcification within ten days, and the 15% compromised sample quality within eight days. Histological analyses confirmed the efficacy of the 10% formic acid concentration in maintaining tissue integrity and achieving optimal staining quality. The standardized protocol presented in this study provides an effective and reliable approach for achieving consistent and high-quality histological sections of rat calvarial bone. An ideal decalcification agent should effectively remove calcium salts, preserve structural integrity and molecular components, facilitate rapid yet minimally damaging decalcification, and ensure ease of handling for laboratory personnel. Further exploration of its applicability to different bone types or species is recommended to broaden its research utility.

I believe I can fly… New implications for the mode of life and palaeoecology of the Late Triassic Ozimek volans based on its unique long bone histology

AbstractThe small diapsid reptile Ozimek volans is one of the most enigmatic representatives of the Late Triassic fauna of Krasiejów, Poland. Phylogenetically, Ozimek was identified as a ‘protorosaurian’ related to tanystropheids, but the extremely elongated limbs and presumed gliding abilities are unusual for this group. This raises the question of whether the lifestyle inferred for this taxon is reflected in its bone histology.Two long bones from a single bone association of Ozimek (humerus UOPB 1148a and femur UOPB 1148b) were sectioned at the midshaft to obtain details of the histological framework. A large medullary cavity, thin walls of lamellar bone with numerous lamellae, and only very few simple vascular canals are shared by both bones. Application of a modified 3‐front model (introducing a fourth front) of cortical growth reveals that the femur is ontogenetically younger when compared to the humerus.Ozimek limb bones, with their small diameter, compact structure, low vascularization, no remodelling, and a lack of pneumaticity, are histologically similar to those of modern small bats. The characteristic cortex of both may have been well suited to withstand high loads while limiting weight. The well‐ordered collagen fibres in successive lamellae along the bone may be a key adaptation for the better distribution of the load generated during gliding. © 2024 The Palaeontological Association.

The Powdered Red Macroalgae (Eucheuma spinosum) Supplementation Potentially Enhanced Bone Structure in Osteoporotic Mice

BACKGROUND: Red macroalgae, such as Eucheuma spinosum, have been found to have potential benefits for bone health due to their unique bioactive compounds, including proteins, polyphenols, polysaccharides, vitamins, and minerals. Therefore, this study was conducted to evaluate the benefits of powdered E. spinosum supplementation in osteoporosis-induced mice.METHODS: Thirty middle-aged mice were divided into 6 groups, namely: healthy control group (HC), negative control group (NC), positive control group (PC), and treatment groups supplemented with 1.25 mg/gBW (T1), 2.5 mg/gBW (T2), and 5 mg/gBW (T3) of E. spinosum powder for twenty days. Mice in NC, PC, T1, T2, and T3 groups were induced with 0.0029 mg/gBW of dexamethasone for 30 days to create osteoporosis mice models. Alkaline phosphatase (ALP) levels were measured by colorimetric methods before and after the intervention. Bone structures were evaluated using X-ray images and histological examination.RESULTS: After the intervention, PC, T1, T2, and T3 groups showed a significant decrease (p≤0.01) in serum ALP levels compared to the NC group, which experienced an increase in ALP levels. The X-ray images revealed that the PC, T1, T2, and T3 showed radiopaque bone density. For bone histology, PC, T2, and T3 showed an improvement with thickened and intact trabeculae, but T1 still had visible osteoporosis cavities.CONCLUSION: Supplementation of 2.5 and 5 mg/gBW of E. spinosum powder were able to improve bone density as well bone histology. Therefore, E. spinosum powder supplementation might potentially improve bone structure in osteoporosis.KEYWORDS: Eucheuma spinosum, red macroalgae, alkaline phosphatase, osteoporosis

Mesenchymal Stem Cell Exosomes Enhance Posterolateral Spinal Fusion in a Rat Model.

Spinal fusion, a common surgery performed for degenerative lumbar conditions, often uses recombinant human bone morphogenetic protein 2 (rhBMP-2) that is associated with adverse effects. Mesenchymal stromal/stem cells (MSCs) and their extracellular vesicles (EVs), particularly exosomes, have demonstrated efficacy in bone and cartilage repair. However, the efficacy of MSC exosomes in spinal fusion remains to be ascertained. This study investigates the fusion efficacy of MSC exosomes delivered via an absorbable collagen sponge packed in a poly Ɛ-caprolactone tricalcium phosphate (PCL-TCP) scaffold in a rat posterolateral spinal fusion model. Herein, it is shown that a single implantation of exosome-supplemented collagen sponge packed in PCL-TCP scaffold enhanced spinal fusion and improved mechanical stability by inducing bone formation and bridging between the transverse processes, as evidenced by significant improvements in fusion score and rate, bone structural parameters, histology, stiffness, and range of motion. This study demonstrates for the first time that MSC exosomes promote bone formation to enhance spinal fusion and mechanical stability in a rat model, supporting its translational potential for application in spinal fusion.

Erythroid Predominance in Bone Marrow Biopsies of Acute Myeloid Leukemia Patients after Decitabine Treatment Correlates with Mutation Profile and Complete Remission

Introduction: Acute myeloid leukemia (AML) patients may receive hypomethylating agents such as decitabine (DAC) as part of their treatment. Not all patients respond to this therapy, and if they do, the clinical response may occur only after 3–6 courses of treatment. Hence, early biomarkers predicting response would be very useful. Methods: We retrospectively analyzed a cohort of 22 AML patients who were treated with DAC. Histology of the bone marrow biopsy, pathogenic mutations, and methylation status were related to the treatment response. Results: In 8/22 (36%) patients, an erythroid dominant response (EDR) pattern, defined as a ratio of myeloid cells/erythroid cells <1, was observed. In the remaining 14 cases, a myeloid predominance was preserved during treatment. No difference in the hypomethylating effect of DAC treatment was observed in patients with and without EDR, as global 5-methylcytosine levels dropped similarly in both groups. Mutational analysis by NGS using a panel of commonly mutated genes in AML showed that patients with an early EDR harbored on average less mutations, with U2AF1 mutations occurring more frequently, whereas RUNX1 mutations were underrepresented compared to non-EDR cases. Interestingly, the development of an EDR correlated with complete remission (7/8 cases with an EDR vs. only 2/14 cases without an EDR). Conclusion: We conclude that early histological bone marrow examination for the development of an EDR may be helpful to predict response in AML patients during treatment with DAC.

The dinosaurs that weren't: osteohistology supports giant ichthyosaur affinity of enigmatic large bone segments from the European Rhaetian.

Very large unidentified elongate and rounded fossil bone segments of uncertain origin recovered from different Rhaetian (Late Triassic) fossil localities across Europe have been puzzling the paleontological community since the second half of the 19th century. Different hypotheses have been proposed regarding the nature of these fossils: (1) giant amphibian bones, (2) dinosaurian or other archosaurian long bone shafts, and (3) giant ichthyosaurian jaw bone segments. We call the latter proposal the 'Giant Ichthyosaur Hypothesis' and test it using bone histology. In presumable ichthyosaur specimens from SW England (Lilstock), France (Autun), and indeterminate cortical fragments from Germany (Bonenburg), we found a combination of shared histological features in the periosteal cortex: an unusual woven-parallel complex of strictly longitudinal primary osteons set in a novel woven-fibered matrix type with intrinsic coarse collagen fibers (IFM), and a distinctive pattern of Haversian substitution in which secondary osteons often form within primary ones. The splenial and surangular of the holotype of the giant ichthyosaur Shastasaurus sikanniensis from Canada were sampled for comparison. The results of the sampling indicate a common osteohistology with the European specimens. A broad histological comparison is provided to reject alternative taxonomic affinities aside from ichthyosaurs of the very large bone segment. Most importantly, we highlight the occurrence of shared peculiar osteogenic processes in Late Triassic giant ichthyosaurs, reflecting special ossification strategies enabling fast growth and achievement of giant size and/or related to biomechanical properties akin to ossified tendons.

A new stegosaurian dinosaur (Ornithischia: Thyreophora) with a remarkable dermal armour from the Middle Jurassic of North Africa

In recent years the Middle Atlas of Morocco has become an area of interest for the study of dinosaurs in northern Africa. The Boulahfa locality, near Boulemane, has produced a diverse dinosaur assemblage from the Middle Jurassic of the El Mers Group. Fossil remains of sauropods and thyreophorans, such as ankylosaurs (Spicomellus) and stegosaurs (Adratiklit), have been reported so far in this region. Here, we describe a new partial thyreophoran skeleton found in the gray marls of the El Mers III Formation (Bathonian-? Callovian), which mainly consists of disarticulated dorsal vertebrae and ribs, and associated dermal armour elements. Axial characters (e.g., elongated pedicels of the dorsal neural arches; upturned transverse processes and dorsal ribs with straight axes suggesting a narrow ribcage) indicate that the specimen belongs to a medium to large-sized stegosaur. The dorsal vertebrae show differences with those of Adratiklit, whose material has been found at the same stratigraphic levels. Thyreosaurus atlasicus gen. et sp. nov. is characterized by a remarkable dermal armour, which consists of thick (up to 4 cm) subovate to subrectangular-shaped osteoderms. The asymmetrical texture of their sides, one roughly ornamented with small pits and fiber bundles, the other with a well-marked cross-hatched pattern, is clearly different from that observed to date in other stegosaurs (and ankylosaurs). The bone histology of these osteoderms is reminiscent of that of stegosaurian tail spines. It is interpreted that these osteoderms were arranged in a recumbent position over the body of the animal, instead of an erect position. The holotype corresponds to an adult individual who did not reach its maximum body size (estimated body length 6 m). The phylogenetic analysis suggests that Thyreosaurus is closely related to Dacentrurus within Dacentrurinae. The recent discoveries of Adratiklit and Thyreosaurus provide insight into the early evolution of stegosaurs in the Middle Jurassic of Africa.