Strontium ranelate prevents the deleterious action of advanced glycation endproducts on osteoblastic cells via calcium channel activation

A Critical Review of Biodegradable Zinc Alloys toward Clinical Applications

Biodegradable zinc (Zn) alloys stand out as promising contenders for biomedical applications due to their favorable mechanical properties and appropriate degradation rates, offering the potential to mitigate the risks and expenses associated with secondary surgeries. While current research predominantly centers on the in vitro examination of Zn alloys, notable disparities often emerge between in vivo and in vitro findings. Consequently, conducting in vivo investigations on Zn alloys holds paramount significance in advancing their clinical application. Different element compositions and processing methods decide the mechanical properties and biological performance of Zn alloys, thus affecting their suitability for specific medical applications. This paper presents a comprehensive overview of recent strides in the development of biodegradable Zn alloys, with a focus on key aspects such as mechanical properties, toxicity, animal experiments, biological properties, and molecular mechanisms. By summarizing these advancements, the paper aims to broaden the scope of research directions and enhance the understanding of the clinical applications of biodegradable Zn alloys.

Microelement strontium and human health: comprehensive analysis of the role in inflammation and non-communicable diseases (NCDs)

Strontium (Sr), a trace element with a long history and a significant presence in the Earth's crust, plays a critical yet often overlooked role in various biological processes affecting human health. This comprehensive review explores the multifaceted implications of Sr, especially in the context of non-communicable diseases (NCDs) such as cardiovascular diseases, osteoporosis, hypertension, and diabetes mellitus. Sr is predominantly acquired through diet and water and has shown promise as a clinical marker for calcium absorption studies. It contributes to the mitigation of several NCDs by inhibiting oxidative stress, showcasing antioxidant properties, and suppressing inflammatory cytokines. The review delves deep into the mechanisms through which Sr interacts with human physiology, emphasizing its uptake, metabolism, and potential to prevent chronic conditions. Despite its apparent benefits in managing bone fractures, hypertension, and diabetes, current research on Sr's role in human health is not exhaustive. The review underscores the need for more comprehensive studies to solidify Sr's beneficial associations and address the gaps in understanding Sr intake and its optimal levels for human health.

Multifunctional Titanium Surfaces for Orthopedic Implants: Antimicrobial Activity and Enhanced Osseointegration

The use of implants in orthopedics and dental practice is a widespread surgical procedure to treat diverse diseases. However, peri-implantitis due to infections and/or poor osseointegration can lead to metallic implant failure. The aim of this study was to develop a multifunctional coating on titanium (Ti) surfaces, to simultaneously deal with both issues, by combining antibacterial silver nanoparticles (AgNPs) and regenerative properties of lactoferrin (Lf). A simple and cost-effective methodology that allows the direct multifunctionalization of Ti surfaces was developed. The modified surfaces were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy, and contact angle measurements. Additionally, in vitro preosteoblast cell adhesion, cell viability, and differentiation were evaluated. The antibacterial capability of the surfaces was tested against Staphylococcus aureus as a prosthesis infection model strain. Our results showed that Lf adsorbed on both Ti surfaces and Ti surfaces with adsorbed AgNPs. Simultaneously, the presence of Lf and AgNPs notably improved preosteoblast adhesion, proliferation, and differentiation, whereas it reduced the bacterial colonization by 97.7%. Our findings indicate that this simple method may have potential applications in medical devices to both improve osseointegration and reduce bacterial infection risk, enhancing successful implantation and patients' quality of life.

[Research progress in the osteogenetic mechanism of strontium]

Strontium (Sr) is an essential trace element and widely exists in nature. It plays an important role in the in vivo regulation of bone metabolism. Sr locates below Fe in the periodic table, and its chemical structure and polarity are similar to those of Ca. It can induce bone mesenchymal stem cells to differentiate into osteoblasts by inhibiting the activity of osteoclasts and reducing bone resorption. It promotes bone formation through a series of related pathways. The mechanism of Sr regulation of bone metabolism has been extensively researched in recent years. The current study aims to investigate the mechanism of Sr and provide a theoretical basis for its clinical application.

Study of Sr-Ca-Si-based scaffolds for bone regeneration in osteoporotic models

Bone tissue engineering has emerged as a promising alternative therapy for patients who suffer bone fractures or defects caused by trauma, congenital diseases or tumours. However, the reconstruction of bone defects combined with osteoporosis remains a great challenge for clinicians and researchers. Based on our previous study, Ca–Si-based bioceramics (MSCs) showed enhanced bone formation capabilities under normal conditions, and strontium was demonstrated to be therapeutic in promoting bone quality in osteoporosis patients. Therefore, in the present study, we attempted to enlarge the application range of MSCs with Sr incorporation in an osteoporotic bone regeneration model to evaluate whether Sr could assist in regeneration outcomes. In vitro readout suggested that Sr-incorporated MSC scaffolds could enhance the expression level of osteogenic and angiogenic markers of osteoporotic bone mesenchymal stem cells (OVX BMSCs). Animal experiments showed a larger new bone area; in particular, there was a tendency for blood vessel formation to be enhanced in the Sr-MSC scaffold group, showing its positive osteogenic capacity in bone regeneration. This study systematically illustrated the effective delivery of a low-cost therapeutic Sr agent in an osteoporotic model and provided new insight into the treatment of bone defects in osteoporosis patients.

Current Knowledge Regarding the Interaction Between Oral Bone Metabolic Disorders and Diabetes Mellitus

Diabetes mellitus, a major chronic disease affecting human health, has been increasing in prevalence in recent years. Diabetes mellitus can cause bone metabolic disorders in patients, leading to osteoporosis, a higher risk of traumatic fracture, and other bone diseases. Bone metabolic disorders in the oral cavity principally manifest as periodontitis, loss of alveolar bone, and failure of implant osseointegration. In recent years, numerous studies have shown that there is a complex interaction between bone metabolic disorders and diabetes mellitus. This paper reviews the adverse effects of diabetes on oral bone metabolism disorders such as alveolar osteoporosis and bone loss in patients with periodontitis, discusses the potential mechanisms of diabetic bone loss, and suggests potential ways to prevent and treat oral bone loss in patients with diabetes mellitus.

Bibliographic review on the state of the art of strontium and zinc based regenerative therapies. Recent developments and clinical applications

This review brings up to date the state of the art of strontium and zinc based regenerative therapies, both having a promoting effect on tissue formation and a role inhibiting resorption in musculoskeletal disorders.

Evaluation of Strontium-Containing PCL-PDIPF Scaffolds for Bone Tissue Engineering: In Vitro and In Vivo Studies

Bone tissue engineering (BTE) has the general objective of restoring and improving damaged bone. A very interesting strategy for BTE is to combine an adequate polymeric scaffold with an osteoinductive compound. Strontium is a divalent cation that can substitute calcium in hydroxyapatite and induce both anabolic and anti-catabolic effects in bone. On the other hand, systemic increases in Sr²⁺ levels can provoke adverse cardiovascular effects. In the present study we have developed a compatibilized blend of poly-ε-caprolactone (PCL) and polydiisopropyl fumarate (PDIPF) enriched with 1% or 5% Sr²⁺ and evaluated the applicability of these biomaterials for BTE, both in vitro and in vivo. In vitro, whereas Blend + 5% Sr²⁺ was pro-inflammatory and anti-osteogenic, Blend + 1% Sr²⁺ released very low quantities of the cation; was not cytotoxic for cultured macrophages; and showed improved osteocompatibility when used as a substratum for primary cultures of bone marrow stromal cells. In vivo, implants with Blend + 1% Sr²⁺ significantly increased bone tissue regeneration and improved fibrous bridging (vs. Blend alone), while neither inducing a local inflammatory response nor increased serum levels of Sr²⁺. These results indicate that our compatibilized blend of PCL-PDIPF enriched with 1% Sr²⁺ could be useful for BTE.

Multi-Scale Approach for the Evaluation of Bone Mineralization in Strontium Ranelate-Treated Diabetic Rats

Long-term diabetes mellitus can induce osteopenia and osteoporosis, an increase in the incidence of low-stress fractures, and/or delayed fracture healing. Strontium ranelate (SrR) is a dual-action anti-osteoporotic agent whose use in individuals with diabetic osteopathy has not been adequately evaluated. In this study, we studied the effects of an oral treatment with SrR and/or experimental diabetes on bone composition and biomechanics. Young male Wistar rats (half non-diabetic, half with streptozotocin/nicotinamide-induced diabetes) were either untreated or orally administered 625 mg/kg/day of SrR for 6 weeks. After sacrifice, femora from all animals were evaluated by a multi-scale approach (X-ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma optical-emission spectrometry, static histomorphometry, pQCT, and mechanical testing) to determine chemical, crystalline, and biomechanical properties. Untreated diabetic animals (versus untreated non-diabetic) showed a decrease in femoral mineral carbonate content, in cortical thickness and BMC, in trabecular osteocyte density, in maximum load supported at rupture and at yield point, and in overall toughness at mid-shaft. Treatment of diabetic animals with SrR further affected several parameters of bone (some already impaired by diabetes): crystallinity index (indicating less mature apatite crystals); trabecular area, BMC, and vBMD; maximum load at yield point; and structural elastic rigidity. However, SrR was also able to prevent the diabetes-induced decreases in trabecular osteocyte density (completely) and in bone ultimate strength at rupture (partially). Our results indicate that SrR treatment can partially but significantly prevent some bone structural mechanical properties as previously affected by diabetes, but not others (which may even be worsened).

Metformin Affects Cortical Bone Mass and Marrow Adiposity in Diet-Induced Obesity in Male Mice

Obesity during maturation can affect the growing skeleton directly and indirectly, although these effects and the mechanisms behind them are not fully understood. Our objective was to determine how a high-fat diet with or without metformin treatment affects skeletal development. We also sought to characterize changes that occur in white adipose tissue, circulating metabolites, lipids, and gut microbiota. A diet-induced obesity C57BL/6J mouse model was used to test the effects of obesity and metformin on bone using bone histomorphometry and microcomputed tomography. Bone marrow adipose tissue was quantified with osmium tetroxide microcomputed tomography and histology. Dual-energy x-ray absorptiometry was used to analyze body composition. Hematoxylin and eosin staining was used to assess changes in white adipose depots, mass spectrometry was used for circulating lipids and protein metabolite analysis, and ribosomal RNA sequencing was used for gut microbiome analysis. Mice fed a high fat-diet since wean displayed increased medullary areas and decreased osteoblast numbers in the long bones; this phenotype was partially normalized by metformin. Marrow and inguinal adipose expansion was also noted in obese mice, and this was partially normalized by metformin. A drug-by-diet interaction was noted for circulating lipid molecules, protein metabolites, and gut microbiome taxonomical units. Obesity was not detrimental to trabecular bone in growing mice, but bone marrow medullary expansion was observed, likely resulting from inhibition of osteoblastogenesis, and this was partially reversed by metformin treatment.

Does Local Application of Strontium Increase Osteogenesis and Biomaterial Osteointegration in Osteoporotic and Other Bone Tissue Conditions: Review of Literature

Osteoporosis and other pathological bone conditions can impair bone regeneration properties, consuming in increased morbidity and decreased quality of life. Changes of bone healing can result in poor osteointegration and surgical failures if implants are used. To overcome and facilitate bone regeneration, more attempts are made to develop an ideal synthetic scaffold with better biocompatibility, osteoconductivity, bioactivity, osteoinductivity and interconnected porosity. It is considered that strontium, being similar to calcium, can be incorporated into the mineral phase of the bone remodeling. This quality had led strontium to be used as an osteoporotic medication to improve quality of bone and to reduce the risk of bone fractures. Also local application of strontium has been widely used within different biomaterials in tissue engineering researches.

In this review authors wanted to provide an overview about strontium, its mechanisms of action in bone tissue and initiated changes of bone remodeling within biomaterials.

Calcium-sensing receptor-ERK signaling promotes odontoblastic differentiation of human dental pulp cells

Activation of the G protein-coupled calcium-sensing receptor (CaSR) has crucial roles in skeletal development and bone turnover. Our recent study has identified a role for activated CaSR in the osteogenic differentiation of human periodontal ligament stem cells. Furthermore, odontoblasts residing inside the tooth pulp chamber play a central role in dentin formation. However, it remains unclear how CaSR activation affects the odontoblastic differentiation of human dental pulp cells (HDPCs). We have investigated the odontoblastic differentiation of HDPCs exposed to elevated levels of extracellular calcium (Ca) and strontium (Sr), and the contribution of CaSR and the L-type voltage-dependent calcium channel (L-VDCC) to this process. Immunochemical staining of rat dental pulp tissue demonstrated that CaSR was expressed at high levels in the odontoblastic layer, moderate levels in the sublayer, and low levels in the central pulp tissue. Although normal HDPCs expressed low levels of CaSR, stimulation with Ca or Sr promoted both CaSR expression and odontoblastic differentiation of HDPCs along with increased expression of odontoblastic makers. These effects were inhibited by treatment with a CaSR antagonist, whereas treatment with an L-VDCC inhibitor had no effect. Additionally, knockdown of CaSR with siRNA suppressed odontoblastic differentiation of Ca- and Sr-treated HDPCs. ERK1/2 phosphorylation was observed in Ca- and Sr-treated HDPCs, whereas CaSR antagonist treatment or CaSR knockdown blocked ERK1/2 phosphorylation. Furthermore, inhibition of ERK1/2 suppressed mineralization of Ca- and Sr-treated HDPCs. These results suggest that elevated concentrations of extracellular Ca and Sr induce odontoblastic differentiation of HDPCs through CaSR activation and the ERK1/2 phosphorylation.

Advanced glycation end products and strontium ranelate promote osteogenic differentiation of vascular smooth muscle cells in vitro: Preventive role of vitamin D

Advanced glycation end products (AGE) have been demonstrated to induce the osteogenic trans-differentiation of vascular smooth muscle cells (VSMC). Strontium ranelate (SR) is an anti-osteoporotic agent that has both anti-catabolic and anabolic actions on bone tissue. However, in the last years SR has been associated with an increase of cardiovascular risk. We hypothesize that SR can increase the osteoblastic trans-differentiation of VSMC and the induction of extracellular calcifications, an effect that could be potentiated in the presence of AGE and inhibited by simultaneous administration of vitamin D. The present results of our in vitro experiments demonstrate that AGE and SR alone or in combination, stimulate L-type calcium channels, causing an increase in reactive oxygen species and activation of both ERK and NFkB, with the final effect of promoting the osteogenic shift of VSMC. Importantly, these in vitro effects of AGE and/or SR can be prevented by co-incubation with vitamin D.

Strontium ranelate effect on bone mineral density is modified by previous bisphosphonate treatment

The aim of this study was to evaluate the effect of strontium ranelate (SrR) on bone mineral density (BMD) and bone turnover markers after 1 year of treatment. Additionally, the effect of SrR in bisphosphonate-naïve patients (BP-naïve) compared to patients previously treated with bisphosphonates (BP-prior) was analyzed. This retrospective study included 482 postmenopausal women treated with SrR (2 g/day) for 1 year in ten Argentine centers; 41 patients were excluded due to insufficient data, while 441 were included. Participants were divided according to previous bisphosphonate treatment in two groups: BP-naïve (n = 87) and BP-prior (n = 350). Data are expressed as mean ± SEM. After 1 year of treatment with SrR the bone formation markers total alkaline phosphatase and osteocalcin were increased (p < 0.0001), while the bone resorption marker s-CTX was decreased (p = 0.0579). Also increases in BMD at the lumbar spine (LS, 3.73%), femoral neck (FN, 2.00%) and total hip (TH, 1.54%) [p < 0.0001] were observed. These increments were significant (p < 0.0001) both among BP-naïve and BP-prior patients. Interestingly, the change in BMD after 1 year of SrR treatment was higher in BP-naïve patients: LS: BP-naïve = 4.58 ± 0.62%; BP-prior = 3.45 ± 0.28% (p = 0.078). FN: BP-naïve = 2.79 ± 0.56%; BP-prior = 2.13 ± 0.29% (p = 0.161). TH: BP-naïve = 3.01 ± 0.55%; BP-prior = 1.22 ± 0.27% (p = 0.0006). SrR treatment increased BMD and bone formation markers and decreased a bone resorption marker in the whole group, with better response in BP-naïve patients.