Strontium is incorporated in different levels into bones and teeth of rats treated with strontium ranelate

The Role of Fe, S, P, Ca, and Sr in Porous Skeletal Lesions: A Study on Non-adult Individuals Using pXRF

Portable X-ray fluorescence is a new tool in the study of human bone. This research aims to investigate if variations in bone elemental concentrations are related with porous skeletal lesions (PSLs). One hundred well-preserved non-adult skeletons aged 0-11 years were selected from the archaeological site Convent of São Domingos, Lisbon (18th-19th century). Measuring a standard reference material and calculating the technical error of measurement assured elemental data reliability. Moreover, measuring soil samples excluded possible contamination of bones with elements from the soil, except for Pb. Additionally, the Ca/P ratio indicates maintenance of bone integrity. Cribra cranii, orbitalia, humeralis, and femoralis were recorded as present/absent, and the estimated intra-/inter-observer errors were low. The multivariate analysis found higher odds of having cribra orbitalia (OR = 1.76; CI = 0.97-3.20) and cribra femoralis (OR = 1.42; CI = 0.73-2.74) in individuals with lower Fe and higher S. Furthermore, higher levels of P, Ca, and Sr increased the odds of individuals developing cribra femoralis (OR = 2.30; CI = 1.23-4.29). Age also correlated with increased odds of exhibiting cribra orbitalia (OR = 1.86; CI = 0.94-3.68), cribra femoralis (OR = 6.97; CI = 2.78-17.45), and cribra humeralis (OR = 8.32; CI = 2.71-25.60). These findings suggest a shared etiology for these three cribras, contrasting with the higher Fe levels in individuals with cribra cranii. Lower Fe and higher S levels in individuals with cribra suggest a complex etiology, possibly involving conditions like megaloblastic or chronic disease anemia(s). Age-related elemental changes support the hypothesis that age influences cribra frequencies. This study highlights PSL complexity and opens new avenues for research.

Applications of Bioactive Strontium Compounds in Dentistry

Divalent cations have captured the interest of researchers in biomedical and dental fields due to their beneficial effects on bone formation. These metallic elements are similar to trace elements found in human bone. Strontium is a divalent cation commonly found in various biomaterials. Since strontium has a radius similar to calcium, it has been used to replace calcium in many calcium-containing biomaterials. Strontium has the ability to inhibit bone resorption and increase bone deposition, making it useful in the treatment of osteoporosis. Strontium has also been used as a radiopacifier in dentistry and has been incorporated into a variety of dental materials to improve their radiopacity. Furthermore, strontium has been shown to improve the antimicrobial and mechanical properties of dental materials, promote enamel remineralization, alleviate dentin hypersensitivity, and enhance dentin regeneration. The objective of this review is to provide a comprehensive review of the applications of strontium in dentistry.

Functional role of inorganic trace elements in dentin apatite tissue-Part 1: Mg, Sr, Zn, and Fe

Many essential elements exist in nature with significant influence on dentin and bone apatite tissue. Hydroxyapatite (HAp) is the major inorganic crystalline structure of dentin that provides a site for various physiological functions such as surface layer ion exchange. Decades of apatite research have shown that enamel is a high-substituted crystalline apatite, but recent findings suggest that dentin apatite may play a more important role in regulating ion exchange as well as mineral crystallinity. This article is the first part of a review series on the functional role of inorganic trace elements including magnesium, strontium, zinc, and iron in dentin hydroxyapatite. The morphology, physiology, crystallinity, and solubility of these elements as they get substituted into the HAp lattice are extensively discussed. An electronic search was performed on the role of these elements in dentin apatite from January 2007 to September 2021. The relationship between different elements and their role in the mineral upkeep of dentin apatite was evaluated. Several studies recognized the role of these elements in dentinal apatite composition and its subsequent effects on morphology, crystallinity, and solubility. These elements are of great importance in physiological processes and an essential part of living organisms. Magnesium and strontium stimulate osteoblast activity, while zinc can improve overall bone quality with its antibacterial properties. Iron nanoparticles are also vital in promoting bone tissue growth as they donate or accept electrons in redox reactions. Thus, understanding how these elements impact dentin apatite structure is of great clinical significance.

The Influence of Strontium on Bone Tissue Metabolism and Its Application in Osteoporosis Treatment

Osteoporosis is a chronic disease characterized by low bone mass caused by increased bone turnover and impaired bone microarchitecture. In treatment, we use antiresorptive or anabolic drugs, which usually have a unidirectional effect, i.e., they inhibit the activity of osteoclasts or stimulate the effect of osteoblasts. Strontium ranelate is an anti-osteoporosis drug with a unique mechanism of action (used primarily in postmenopausal women). Unlike other medicines, it has a multidirectional effect on bone tissue, intensifying osteoblastogenesis while inhibiting osteoclastogenesis. It turns out that this effect is demonstrated by strontium ions, an element showing physical and chemical similarity to calcium, the basic element that builds the mineral fraction of bone. As a result, strontium acts through the calcium-sensing receptor (CaSR) receptor in bone tissue cells. In recent years, there has been a significant increase in interest in the introduction of strontium ions in place of calcium ions in ceramics used as bone replacement materials for the treatment of bone fractures and defects caused by osteoporosis. The aim of this study was to summarize current knowledge about the role of strontium in the treatment of osteoporosis, its effects (in various forms), and the ways in which it is administered.

The Effect of Sensory Innervation on the Inorganic Component of Bones and Teeth; Experimental Denervation - Review

The effect of the nervous system on bone remodelling has been described by many studies. Sensory and autonomic nerves are present in the bone. Immunohistochemical analysis of the bone have indicated the presence of neuropeptides and neurotransmitters that act on bone cells through receptors. Besides carrying sensory information, sensory neurons produce various neuropeptides playing an important role in maintaining bone and tooth pulp homeostasis, and dentin formation. Bone tissue and teeth contain organic and inorganic components. Bone cells enable bone mineralization and ensure its formation and resorption. Studies focused on the effects of the nervous system on the bone are proceeded using various ways. Sensory denervation itself can be achieved using capsaicin causing chemical lesion to the nerve. Surgical ways of causing only sensory lesion to nerves are substantially limited because many peripheral nerves are mixed and contain a motor component as well. From this point of view, the experimental model with transection of inferior alveolar nerve is appropriate. This nerve provides sensory innervation of the bone and teeth of the mandible. The purpose of our paper is to provide an overview of the effects exerted by the nervous system on the inorganic component of the bone and teeth, and also to present an overview of the used experimental models. As we assume, the transection of inferior alveolar nerve could be reflected in changed contents and distribution of chemical elements in the bone and teeth of rat mandible. This issue has not been studied so far.

Effect of Strontium Ranelate on the Muscle and Vertebrae of Ovariectomized Rats

Osteoporosis is often accompanied by sarcopenia. The effect of strontium ranelate (SR) on muscle tissue has not been investigated sufficiently. In this study, the effect of different SR treatments on muscle was studied. Additionally, the lumbar vertebrae were analyzed. Three-month-old female rats were divided into five groups (n = 12): Group 1: untreated (NON-OVX); Group 2: ovariectomized and left untreated (OVX); Group 3: SR after OVX until the study ended (13 weeks, SR prophylaxis and therapy = pr+th); Group 4: OVX and SR for 8 weeks (SR prophylaxis = pr); Group 5: SR for 5 weeks from the 8 week after OVX (SR therapy = SR th). SR was applied in food (630 mg/kg body weight). The size of muscle fibers, capillary density, metabolic enzymes, and mRNA expression were assessed in soleus, gastrocnemius, and longissimus muscles. The vertebral bodies underwent micro-CT, biomechanical, and ashing analyses. In general, SR did not alter the muscle histological parameters. The changes in fiber size and capillary ratio were related to the body weight. Myostatin mRNA was decreased in Sr pr+th; protein expression was not changed. SR th led to increase in mRNA expression of vascular endothelial growth factor (Vegf-B). In lumbar spine, SR pr+th enhanced biomechanical properties, bone mineral density, trabecular area, density, and thickness and cortical density. The reduced calcium/phosphate ratio in the SR pr+th group indicates the replacement of calcium by strontium ions. SR has no adverse effects on muscle tissue and it shows a favorable time-dependent effect on vertebrae. A functional analysis of muscles could verify these findings.

Multielemental Chemical Analysis of Elements in Mandibular Bone and Teeth in the Rat

The purpose of the study was to test the hypothesis of different distribution spaces of elements in the rat mandibular bone and teeth. We used six adult males of Wistar laboratory rats for the study. After killing the animals, we extracted the molars and removed incisor crowns. The mandibular bone was divided into four parts (mesial-central-distal-ridge). Inductively coupled plasma mass spectrometry was used to determine the presence of 41 elements in the bone and tooth. Evidence of 14 elements was found in all samples (incisors-molarsbone). Generally, significant differences between the left and right side were found for K and Rb in the bone locations. As regards statistically significant differences in incisors-molars-bone locations, the elements for which these differences were found for all comparisons are listed as incisors versus individual molars, incisors versus bone locations, and individual molars versus bone locations: a) incisors-molars: Ba, Mn, Mo, Sr, Zn, K, Mg and Rb; b) incisors-bone: Fe, K, Mg, Mn, Na, Zn and Ba; c) molars-bone: Mn, Mo, Na and Mg. Statistically significant differences were also found between molars for Fe, Mg, Mn, and Sr and between bone locations for Ba, Ca, Mn, Sr, K, Rb, Zn, Mo, Mg, and Na. The elements Cu, Ni and Co were without pronounced differences. Twenty-seven elements were below the detection limit. Our results indicate different distributions of some elements in the rat mandibular incisors-molars-bone. We assume that the knowledge of chemical element contents in the laboratory rat bone and teeth will prove useful in experimental research of both these hard tissues.

Strontium ranelate improves the interaction of osteoblastic cells with titanium substrates: Increase in cell proliferation, differentiation and matrix mineralization

We describe direct effects of strontium ranelate on the interaction of osteoblastic cells with different titanium substrates. Our goal was to better understand the potential of this drug for improving the efficacy of bone implants. Treatment was done with 0.12 and 0.5 mM Sr(2+) of strontium ranelate in cell culture. We analyzed cell response to the drug on titanium substrates with surface topographies obtained using acid etching, electro-erosion processing, sandblasting, and machine-tooling. Treatment preserved the initial cell adhesion to the substrates, cell shape parameters (area, aspect ratio, circularity, and solidity), and the orientation of cells on grooved surfaces. However, both concentrations of the drug increased cell proliferation in all substrates. Moreover, a dose-dependent increase in alkaline phosphatase activity and in the production of mineralized matrix with typical features of bone tissue was shown. The observed effects were similar in the different substrates. In conclusion, strontium ranelate improved the interaction of osteoblastic cells with titanium substrates, increasing cell proliferation and differentiation into mature osteoblasts and the production of bone-like mineralized matrix for all substrates. This study highlights a promising role of strontium ranelate on enhancing the clinical success of bone implants, particularly in patients with osteoporosis.

Zinc asparaginate supplementation induces redistribution of toxic trace elements in rat tissues and organs

The primary objective of the current study was the investigation of the influence of zinc asparaginate supplementation for 7 and 14 days on toxic metal and metalloid content in rat organs and tissues. Rats obtained zinc asparaginate in doses of 5 and 15 mg/kg/day for 7 and 14 days. At the end of the experiment rat tissues and organs (liver, kidney, heart, m. gastrocnemius, serum, and hair) were collected for subsequent analysis. Estimation of Zn, Al, As, Li, Ni, Sn, Sr content in the harvested organs was performed using inductively coupled plasma mass spectrometry at NexION 300D. The obtained data showed that intragastric administration of zinc significantly increased liver, kidney and serum zinc concentrations. Seven-day zinc treatment significantly affected the toxic trace element content in the animals’ organs. Zinc supplementation significantly decreased particularly liver aluminium, nickel, and tin content, whereas lead tended to increase. Zinc-induced changes in kidney metal content were characterized by elevated lithium and decreased nickel concentration. Zinc-induced alteration of myocardical toxic element content was multidirectional. Muscle aluminium and lead concentration were reduced in response to zinc supplementation. At the same time, serum and hair toxic element concentrations remained relatively stable after 7-day zinc treatment. Zinc asparaginate treatment of 14 days significantly depressed liver and elevated kidney lithium content, whereas a significant zinc-associated decrease was detected in kidney strontium content. Zinc supplementation for 14 days resulted also in multidirectional changes in the content of heart toxic elements. At the same time, significant zinc-associated decrease in muscle lithium and nickel levels was observed. Fourteen-day zinc treatment resulted in significantly increased serum arsenic and tin concentrations, whereas hair trace element content remained relatively stable. Generally, the obtained data indicate a significant redistribution of toxic metals in the animal organism under zinc supplementation.

The effects of strontium on bone mineral: A review on current knowledge and microanalytical approaches

The interest in effects of strontium (Sr) on bone has greatly increased in the last decade due to the development of the promising drug strontium ranelate. This drug is used for treating osteoporosis, a major bone disease affecting hundreds of millions of people worldwide, especially postmenopausal women. The novelty of strontium ranelate compared to other treatments for osteoporosis is its unique effect on bone: it simultaneously promotes bone formation by osteoblasts and inhibits bone resorption by osteoclasts. Besides affecting bone cells, treatment with strontium ranelate also has a direct effect on the mineralized bone matrix. Due to the chemical similarities between Sr and Ca, a topic that has long been of particular interest is the incorporation of Sr into bones replacing Ca from the mineral phase, which is composed by carbonated hydroxyapatite nanocrystals. Several groups have analyzed the mineral produced during treatment; however, most analysis were done with relatively large samples containing numerous nanocrystals, resulting thus on data that represents an average of many crystalline domains. The nanoscale analysis of the bone apatite crystals containing Sr has only been described in a few studies. In this study, we review the current knowledge on the effects of Sr on bone mineral and discuss the methodological approaches that have been used in the field. In particular, we focus on the great potential that advanced microscopy and microanalytical techniques may have on the detailed analysis of the nanostructure and composition of bone apatite nanocrystals produced during treatment with strontium ranelate.

Comparison of chemical composition of enamel and dentine in human, bovine, porcine and ovine teeth

OBJECTIVE

The aim of this paper was to compare the chemical composition of human teeth with other mammal species that are likely candidates for replacing them in studies that test dental material.

DESIGN

Dentine and enamel fragments extracted from 400 sound human, bovine, porcine and ovine - 100 teeth per species - incisors and molars were mechanically ground up to a final particle size of less than 100 μm. C/N analysis, thermogravimetric analysis coupled to mass spectrometry (TG-MS), and wavelength dispersive X-ray fluorescence (WDXRF) were used to analyse the samples' composition.

RESULTS

Elemental analysis showed more organic carbon and nitrogen in dentine than in enamel. Human enamel was the most highly mineralised, with C and N values close to hydroxyapatite. Bovine dentine and enamel were the most similar to human. TG-MS: in all species, enamel contained less carbon and organic matter than dentine. Thermal decomposition of human enamel showed great similarity to synthetic hydroxyapatite, and large differences from bovine, ovine and porcine enamel. Thermal decomposition showed the greatest similarity between human and bovine dentine.

WDXRF

Dentine contained larger quantities of Mg, S, Sr and Zn than enamel. Enamel contained larger quantities of P, Ca, Cl, Cu, K and Ca/P ratio than dentine. Human enamel and dentine contained a higher Ca/P ratio, larger quantities of Cl and Cu and lower quantities of Mg, S, Zn than the animal species.

CONCLUSIONS

Elemental analysis, TG-MS and WDXRF have shown that human and bovine enamel and dentine show the greatest similarity among the species analysed.

Monitoring bone strontium intake in osteoporotic females self-supplementing with strontium citrate with a novel in-vivo X-ray fluorescence based diagnostic tool

Ten female volunteers were recruited as part of the Ryerson and McMaster University Strontium (Sr) in Bone Research Study to have their bone Sr levels measured as they self-supplemented with Sr supplements of their choice. Of the ten volunteers, nine were suffering from osteopenia and/or osteoporosis. Non-invasive bone Sr measurements were performed using an in vivo x-ray fluorescence (IVXRF) I-125 based system. Thirty minute measurements were taken at the finger and ankle, representing primarily cortical and trabecular bone, respectively. For analysis, the 14.2keV Sr K-alpha peak normalized to the Coherent peak at 35.5keV was used. Baseline readings, representing natural bone Sr levels were acquired since all volunteers had no previous intake of Sr based supplements or medications. Once Sr supplements were started, a 24h reading was taken, followed by frequent measurements ranging from weekly, biweekly to monthly. The longest volunteer participation was 1535days. The mean baseline Sr signal observed for the group was 0.42±0.13 and 0.39±0.07 for the finger and ankle, respectively. After 24h, the mean Sr signal rose to 1.43±1.12 and 1.17±0.51, for the finger and ankle, respectively, representing a statistically significant increase (p=0.0043 & p=0.000613). Bone Sr levels continued to increase throughout the length of the study. However the Sr signal varied widely between the individuals such that after three years, the highest Sr signal observed was 28.15±0.86 for the finger and 26.47±1.22 for the ankle in one volunteer compared to 3.15±0.15 and 4.46±0.36, for the finger and ankle, respectively in another. Furthermore, while it was previously reported by our group, that finger bone Sr levels may plateau within two years, these results suggest otherwise, indicating that bone Sr levels will continue to rise at both bone sites even after 4years of Sr intake.

Strontium localization in bone tissue studied by X-ray absorption spectroscopy

Strontium has recently been introduced as a pharmacological agent for the treatment and prevention of osteoporosis. We determined the localization of strontium incorporated into bone matrix from dogs treated with Sr malonate by X-ray absorption spectroscopy. A new approach for analyzing the X-ray absorption spectra resulted in a compositional model and allowed the relative distribution of strontium in the different bone components to be estimated. Approximately 35-45% of the strontium present is incorporated into calcium hydroxyapatite (CaHA) by substitution of some of the calcium ions occupying highly ordered sites, and at least 30% is located at less ordered sites where only the first solvation shell is resolved, suggesting that strontium is surrounded by only oxygen atoms similar to Sr(2+) in solution. Strontium was furthermore shown to be absorbed in collagen in which it obtains a higher structural order than when present in serum but less order than when it is incorporated into CaHA. The total amount of strontium in the samples was determined by inductively coupled plasma mass spectrometry, and the amount of Sr was found to increase with increasing dose levels and treatment periods, whereas the relative distribution of strontium among the different components appears to be independent of treatment period and dose level.

Strontium ranelate: in search for the mechanism of action

Strontium ranelate is a medicine with evidenced effects on the risk of fractures. The heterogeneity of strontium distribution in bone, quality of bone mineral crystals in young bone packets on bone surfaces formed during strontium ranelate administration, and activation of the calcium sensing receptor may, at least partially, explain the beneficial effects of SrR on reducing the risk of fractures. In this review, the concept of the dual action of strontium ranelate is also discussed. However, sufficient evidence for the bone anabolic effect of SrR does not exist in humans. The knowledge of the mechanism of action of SrR is important not only for the explanation of the effects of SrR upon the skeleton, but also for the safety of treatment for other tissues.

Strontium ranelate increases the formation of bone-like mineralized nodules in osteoblast cell cultures and leads to Sr incorporation into the intact nodules

We describe effects of strontium ranelate treatment on intact mineralized nodules produced in osteoblast cell cultures. We analyzed the matrix directly at the cell culture surfaces following treatment with 0.05 and 0.5 mM Sr(2+). This method allowed for data to be obtained from intact nodules, rather than from extracted samples. The bone-like nature of the matrix was evaluated by using attenuated total reflection Fourier transform infrared spectroscopy and the incorporation of Sr into the nodules was investigated by using both energy dispersive X-ray spectroscopy and synchrotron radiation micro X-ray fluorescence. We observed typical mineralized nodules in all of the cell cultures. However, the formation of these nodules was markedly increased in cultures treated with 0.5 mM Sr(2+). In all of the cultures, the nature of the intact matrix was similar to that described in native bone tissue, being comprised of a poorly crystalline CO3 (2-)-containing apatite and a collagenous matrix. This indicated that treatment had no deleterious effects on the matrix. Moreover, the nodules presented Ca and P as the main chemical components, confirming their bone-like mineralized nature. The incorporation of Sr into the nodules was clearly observed in the treated cultures, with their relative Sr content [Sr/(Ca+Sr) ratio] being markedly increased in a dose-dependent manner. Thus, strontium ranelate promoted an increase in the formation of mineralized nodules in osteoblast cell cultures while preserving the bone-like nature of the matrix at the tissue level. We further demonstrated that Sr was incorporated into the intact nodules formed during treatment.

Evaluation of strontium introduced apatite cement as the injectable bone substitute developments

We have developed bone cement introducing Strontium (Sr) to promote early bone regeneration. To prolong the release duration of Sr, we applied inorganic Sr filler for containing into the cement powder. The purpose of this study is to evaluate the mechanical properties, crystallinic properties, and ion release activities, especially Sr anion, of this cement. Alpha-TCP powder was mixed with Sr filler, with 0.1wt%, 0.5wt%, 1.0wt%, and 5.0wt%. These were mixed with mixing liquid and formed for each test. They were incubated and crystalized in 95% moisture for 1 week. The mechanical properties were studied by the compression, the diametral tensile strength and 4-point vending. Tested specimens were evaluated by X-ray diffraction(XRD) and scanning electron microscopic(SEM) imaging. The ion release behaviors were measured by inductively coupled plasma mass spectrometry(ICP-MS). The mechanical properties were increased in consistency of filler, but decreased in some samples because of declining the apatite matrix. And the Sr release showed interesting results as the sequential resource of Sr. By adjusting the mixing ratio or considering the application of these Sr releasable cements, this material would show good performance by its strength and longer Sr release for bone regeneration.