Bone Tissue In Osteoporosis Research Articles

Possible involvement of HtrA1 serine protease in the onset of osteoporotic bone extracellular matrix changes

High-temperature requirement A1 (HtrA1), a multidomain serine protease acting on Extracellular matrix (ECM) rearrangement, is also secreted by osteoblasts and osteoclasts. Recent and conflicting literature highlights HtrA1's role as a controller of bone remodeling, proposing it as a possible target for pathologies with unbalanced bone resorption, like Osteoporosis (OP). To add knowledge on this molecule function in bone physiopathology, here we compared HtrA1 distribution in the ECM of healthy (H) and OP bone tissue, also examining its localization in the sites of new bone formation. HtrA1 was homogeneously expressed in the mature bone ECM of H tissue showing a 55.6 ± 16.4% of the stained area, with a significant (p=0.0001) decrease in OP percentage stained area (21.1 ± 13.1). Moreover, HtrA1 was present in the endosteum and cells involved in osteogenesis, mainly in those “entrapped” in woven bone, whereas osteocytes in mature lamellar bone were negative. Based on our previous observation in OP tissue of a significantly increased expression of Decorin and Osteocalcin, both involved in bone mineralization and remodeling and equally substrates for HtrA1, we speculate that HtrA1 by controlling the proper amount of Decorin and Osteocalcin favors normal bone maturation and mineralization. Besides, we suggest that late-osteoblasts and pre-osteocytes secrete HtrA1 in the adjacent matrix whilst proceeding with their maturation and that HtrA1 expression is further modified during the remodeling from woven to the lamellar bone. Overall, our data suggest HtrA1 as a positive regulator of bone matrix formation and maturation: its reduced expression in mature OP bone, affecting protein content and distribution, could hamper correct bone remodeling and mineralization.

Comparisons of gene expression between peripheral blood mononuclear cells and bone tissue in osteoporosis.

Osteoporosis (OP) is one of the major public health problems in the world. However, the biomarkers between the peripheral blood mononuclear cells (PBMs) and bone tissue for prognosis of OP have not been well characterized. This study aimed to explore the similarities and differences of the gene expression profiles between the PBMs and bone tissue and identify potential genes, transcription factors (TFs) and hub proteins involved in OP. The patients were enrolled as an experimental group, and healthy subjects served as normal controls. Human whole-genome expression chips were used to analyze gene expression profiles from PBMs and bone tissue. And the differentially expressed genes (DEGs) were subsequently studied using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. The above DEGs were constructed into protein-protein interaction network. Finally, TF-DEGs regulation networks were constructed. Microarray analysis revealed that 226 DEGs were identified between OP and normal controls in the PBMs, while 2295 DEGs were identified in the bone tissue. And 13 common DEGs were obtained by comparing the 2 tissues. The Gene Ontology analysis indicated that DEGs in the PBMs were more involved in immune response, while DEGs in bone were more involved in renal response and urea transmembrane transport. And the Kyoto Encyclopedia of Genes and Genomes analysis indicated almost all of the pathways in the PBMs were overlapped with those in the bone tissue. Furthermore, protein-protein interaction network presented 6 hub proteins: PI3K1, APP, GNB5, FPR2, GNG13, and PLCG1. APP has been found to be associated with OP. Finally, 5 key TFs were identified by TF-DEGs regulation networks analysis (CREB1, RUNX1, STAT3, CREBBP, and GLI1) and were supposed to be associated with OP. This study enhanced our understanding of the pathogenesis of OP. PI3K1, GNB5, FPR2, GNG13, and PLCG1 might be the potential targets of OP.

Dental implants osseointegration in patients with osteoporosis

The successful use of surgical and medical methods of jaw bone tissue restoration has been convincingly confirmed in clinical practice. At the same time, technologies are being developed to improve the osseointegration of dental implants in patients with osteoporosis. The use of various implant coatings, as well as systemic therapy, demonstrate the emergence of new directions in the treatment of patients with partial or complete secondary edentulism with concomitant osteoporosis. This trend is relevant in modern medicine . Information was obtained from the PubMed database, using the keywords «osteoporosis» and «osseointegration» and «dental implantation» and «zoledronic acid» from 2016 to 2022. Articles were selected based on experimental work. Numerous studies have shown that bone tissue is an effective indicator of osteoporotic changes. The main changes in bone tissue in osteoporosis are emphasized - a decrease in bone volume, deterioration of the microarchitecture of the trabecular bone and processes that prevent osseointegration - loss of bone mass, a significant decrease in the percentage of contact in the implant-bone complex. Methods of dealing with the negative impact on the operation of dental implantation have been identified. In a review of studies on the systemic administration of drugs based on bisphosphonates, an increase in the osseointegration of dental implants was revealed, the systemic administration of zoledronic acid preparations significantly increased the formation of new bone, which in turn contributed to the elimination of such a negative effect of osteoporosis as bone resorption. In addition to the systemic administration of bisphosphonates, experimental studies describe the topical application of bisphosphonates in the form of various implant coatings. Topical application of bisphosphonates also contributed to increased osseointegration. Microstructured coated implants showed less marginal bone loss compared to uncoated implants. Conclusion. The use of dental implants with modified macro- and microrelief, as well as systemic drug therapy, remains the main direction of scientific research that contributes to the optimization of osseointegration of dental implants.

Динаміка рентгенологічних показників у хворих на деструктиві форми апікального періодонтиту в віддалені лікувальні терміни

The purpose of the study was to evaluate the effectiveness of the proposed treatment based on changes in radiological parameters in patients with destructive forms of apical periodontitis in the long term. Materials and methods. During the study, 185 patients with destructive forms of apical periodontitis were examined and treated. They were divided into 4 groups. Measurements of the size of the lesion in the bone tissue (for lesions of round shape) were performed by the formula: S = πr2; for lesions of elliptical shape: S = π ab, where π = 3.14; r – the radius of the circle; a – the value of the major half-axis of the ellipse; b – the length of the small half-axis of the ellipse. Results and discussion. When evaluating X-rays pictures in the treating group IV, where ("Platelet-Rich Plasma + mp3 OsteoBiol") was used for root canal obturation, after 6 months of observation, in 19 people (40.43%) foci of destruction of the bone tissue of the apical area of 1.5 mm2 and less were visualized. It was characteristic of this group of persons that there was a decrease in their number of bone tissue destruction area in sizes: 1.6 - 20 mm2 – by 1.7 times; 21 - 30 mm2 – by 2.0 times; 31 - 40 mm2 – by 2.5 times; 41 - 51 and more mm2 – by 1.3 times. It should be noted that this trend convincingly demonstrates a significant reduction in bone tissue of the periapical area in patients of group IV, and indicates in favor of the adequacy of the applied therapy using our proposed osteotropic composition. X-ray evaluation of the results of treatment of patients of group IV, in whom for the treatment of destructive forms of apical periodontitis our proposed composition ("Platelet-Rich Plasma + mp3 OsteoBiol") was used, after 12 months of research showed that in 29 patients (61.70%) foci of destruction of the apical area were not visualized; in 14 people (29.79%) the foci of osteoporosis bone tissue in the apical area were 1.5 mm2 or less. At the same time, no lesions ranging in size from 1.6 mm2 to 30 mm2 were identified in the treated group IV. At the same time, we determined a decrease in the number of treated with lesion areas: 31 - 40 mm2 – by 2.0 times; 41 - 50 mm2 – by 3.0 times and 51 mm2 and more – by 1.5 times. After 12 months of follow-up in patients of group IV, Rtg score of bone destruction was 4.27±0.61 points, which was probably higher than in patients of I, II, p, p1 <0,01, and III study groups, p2 <0.05. It was noted that at the areas of destruction of cell tissue of the periapical area from 1.6 mm2 to 30 mm2, Rtg score with a value of 5.0±0.71 points, indicated a complete restoration of bone structure; from 31 mm2 to 50 mm2 – for the reduction of the periapical process more than 1/2 and for the area of 51 mm2 and more – for the reduction of the periapical process from 1/3 to 1/2

Interindividual and intraspecimen variability of 3-D bone microarchitectural parameters in iliac crest biopsies imaged by conventional micro-computed tomography

Bone microarchitecture of the iliac bone is used to characterize the properties of bone tissue in osteoporosis, particularly in pharmacological studies. Trabecular bone is known to be heterogeneous media. For a few years, the analysis of three-dimensional (3-D) bone microarchitecture has been based on micro-computed tomography (micro-CT). To assess the interindividual variability (inter-indVar) and the intrasample variability (intra-sampVar) of iliac crest biopsies, we used a Bordier needle trephine in 35 postmenopausal female cadavers (mean age, 74.4 +/- 10.4 years). Finally, we had at our disposal 32 individual iliac crests to assess the inter-indVar and 21 oriented specimens to assess the intra-sampVar. All the samples were chemically defatted, and the images were performed with a desktop micro-CT with a voxel size of 10.77 microm. We measured trabecular bone parameters: bone volume/tissue volume (BV/TV %), trabecular thickness and spacing (Tb. Th*, Tb.Sp* microm), bone surface/bone volume (BS/BV, 1/mm), the trabecular number (Tb.N, 1/mm), structure model index (SMI), trabecular pattern factor (Tb.Pf), and degree of anisotropy (DA). We also measured cortical bone parameters: cortical thickness (Cort.Th), porosity (PoV/TV), and pore diameter (Po.Dm). For the inter-indVar, we analyzed a fixed volume of interest corresponding to 119.8 mm(3) centered on each iliac crest. To assess the intra-sampVar, we divided the whole trabecular volume into three equal height parts (external, middle, internal). BV/TV, Tb.N, and PoV/TV were negatively correlated with age and Tb.Sp* and SMI were positively correlated. The mean difference of absolute individual variations in percentage with the middle area used as a reference, comparatively to external and internal areas, ranged from 6.6% (Tb.Sp*) to 27.8% (BV/TV), except Tb.Pf, which showed large variability. There was no difference between external and internal areas, with a tendency for lower values of BV/TV, Tb.Th*, and Tb.N in the middle of the iliac crest and higher values of Tb.Sp* and BS/BV. The evaluation of bone microarchitecture of iliac crest samples on micro-CT images is reliable. The heterogeneity of bone inside the iliac crest is noticeable as leading to analyzing the largest possible quantity of bone, with standardized location, according to cortex but without any assumption of orientation.

On the potential use of stimulated positron emission (SPE) in the detection and monitoring of some bone diseases.

The feasibility of a new method for in vivo regional measurement of the loss of bone tissue in osteoporosis and bone mineral in osteomalacia has been studied analytically. A cross section in the patient's body containing the bone is excited by high energy x rays (hν>1.022 MeV) to produce positron–electron pairs. The positron distribution is imaged by detecting the resulting annihilations using two detectors placed on opposite sides of the irradiated slice and focused to receive annihilations produced inside the bone. Since the cross section for pair production is proportional to the square of the atomic number of the absorber, any pathological processes involving demineralization or loss of bone tissue are expected to strongly affect the number of counts received from the region imaged. This technique is unique among other radiological procedures for bone measurements in its direct three‐dimensional imaging capability. It has no fundamental limit on precision, and higher precision is achieved by resorting to higher dose or greater bony volume irradiated. In addition, the measurement can be confined to an anatomically and physiologically appropriate bone site, thus maximizing the signal and minimizing interference from surrounding tissues. Using radiological models for osteoporosis and osteomalacia, it is shown that a high sensitivity to small changes (∼5%) in density or amount of mineral of cortical bone can be obtained with a relatively low radiation dose (<0.5 rad). With the same radiation dose, the method is less sensitive to changes in vertebral bone, due to the lower mineral fraction in this type of bone. The dependence of sensitivity on incident x‐ray energy is studied, and it is shown that the optimum energy, from a point of view of maximizing sensitivity while minimizing the loss of spatial resolution due to positron range lies at between 2 and 3 MeV. Finally, the application of the technique in the detection and monitoring of bone cancer and tumors metastatic to bone is suggested.

Some Results of the Effect of Fluoride on Bone Tissue in Osteoporosis

ABSTRACT Three cases are reported in which fluoride was administered to individuals with osteoporosis. Bone biopsies taken after 7 to 24 months of therapy show that the effect of fluoride on bone tissue appears to be stimulation of new bone formation. If calcium and vitamin D are not administered with the fluoride, the new bone is largely uncalcified; however, if an increase in calcium absorption is produced, then the new bone tissue appears relatively normal.