Curcumin alleviates glucocorticoid-induced osteoporosis through the regulation of the Wnt signaling pathway

Antiosteoporosis and Bone Protective Effect of Phyllanthin Against Glucocorticoid-induced Osteoporosis in Rats via Alteration of HO-1/Nrf2 and RANK/RANKL/OPG Pathway

Osteoporosis is a condition where bones weaken due to a loss in density and quality, making them fragile and more susceptible to fractures, even from minor stress or injury. In this experimental study, we scrutinized the antiosteoporosis effect of phyllanthin against glycocorticoid (GIOP) induced osteoporosis in rats.

METHODS

: SD rats were used in this study and subcutaneous administration of DEX (3 mg/kg) was used for the induction of osteoporosis and rats were treated with phyllanthin and alendronate for 12 weeks. The body weight, femur mass, length, hormones, nutrients, antioxidant, cytokines and bone parameters were estimated. The mRNA expression of HO-1, Nrf2, RANK, RANKL and OPG were estimated.

RESULTS

: Phyllanthin treatment significantly (p < 0.001) improved the body weight, femur mass and femur length. Phyllanthin significantly (p < 0.001) altered the level of hormones estrodiol, PTH; nutrients such as calcium, phosphorus, magnesium; Bone mineral content (BMC) and bone mineral density (BMD); Bone formation marker like ALP, TRAP, osteocalcin, β-CTX, BGP, cathepsin K, DPD; Bone parameters viz., Tb.N, BV/TV, Tb.sp, BS/BV, Tb.Th; Bone structure analysis includes maximum load, energy, stiffness, maximum stress, young's modules; oxidative stress parameters such as TBARS, CAT, GPx, GSH, GR; cytokines such as TNF-α, IL-1β, IL-6, IL-10 and antioxidant marker such as HO-1 and Nrf2. Phyllanthin significantly (P < 0.001) altered the mRNA expression of HO-1, Nrf2, RANK, RANKL and OPG.

CONCLUSION

: On the basis of result, we can say that phyllanthin exhibited the antiosteoporosis effect against glucocorticoid-induced osteoporosis in rats via alteration of HO-1/Nrf2 and RANK/RANKL/OPG pathway.

Palm Tocotrienol Activates the Wnt3a/β-Catenin Signaling Pathway, Protecting MC3T3-E1 Osteoblasts from Cellular Damage Caused by Dexamethasone and Promoting Bone Formation

Background and aim: Prolonged glucocorticoid (GC) treatment increases oxidative stress, triggers apoptosis of osteoblasts, and contributes to osteoporosis. Tocotrienol, as an antioxidant, could protect the osteoblasts and preserve bone quality under glucocorticoid treatment. From this study, we aimed to determine the effects of tocotrienol on MC3T3-E1 murine pre-osteoblastic cells treated with GC. Methods: MC3T3-E1 cells were exposed to dexamethasone (150 µM), with or without palm tocotrienol (PTT; 0.25, 0.5, and 1 µg/mL). Cell viability was measured by the MTS assay. Alizarin Red staining was performed to detect calcium deposits. Cellular alkaline phosphatase activity was measured to evaluate osteogenic activity. The expression of osteoblastic differentiation markers was measured by an enzyme-linked immunoassay. Results: Enhanced matrix mineralization was observed in the cells treated with 0.5 µg/mL PTT, especially on day 18 (p < 0.05). The expression of Wnt3a, β-catenin, collagen 1α1, alkaline phosphatase, osteocalcin, low-density lipoprotein receptor-related protein 6, and runt-related transcription factor-2 were significantly increased in the PTT-treated groups compared to the vehicle control group, especially at 0.5 µg/mL of PTT (p < 0.05) and on day 6 of treatment. Conclusions: PTT maintains the osteogenic activity of the dexamethasone-treated osteoblasts by promoting their differentiation.

USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 expression

Dysregulated bone homeostasis contributes to multiple diseases including osteoporosis (OP). In this study, osteoporotic mice were successfully generated using ovariectomy to investigate the role of nuclear receptor subfamily 3 group C member 1 (NR3C1) in OP. NR3C1, identified as a significantly upregulated gene in OP using bioinformatic tools, was artificially downregulated in osteoporotic mice. NR3C1 expression was significantly elevated in the femoral tissues of osteoporotic patients, and downregulation of NR3C1 alleviated bone loss and restored bone homeostasis in osteoporotic mice, as manifested by increased ALP- and OCN-positive cells and reduced RANKL/OPG ratio. Downregulation of NR3C1 inhibited osteoclastic differentiation of RAW264.7 cells and mouse bone marrow-derived macrophages (BMDM) and promoted osteogenic differentiation of MC3T3-E1 cells. The transcription factor NR3C1 bound to the cystatin-3 (CST3) promoter to repress its transcription in both RAW264.7 and MC3T3-E1 cells. The downregulation of CST3 reversed the protective effect of NR3C1 downregulation against OP. Ubiquitin-specific-processing protease 10 (USP10)-mediated deubiquitination of NR3C1 improved NR3C1 stability. Downregulation of USP10 inhibited osteoclastic differentiation of RAW264.7 cells and BMDM while promoting osteogenic differentiation of MC3T3-E1 cells. Taken together, USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 transcription, providing an attractive therapeutic strategy to alleviate OP.

Anti-inflammatory, antiosteoporotic, and bone protective effect of hydroxysafflor yellow A against glucocorticoid-induced osteoporosis in rats

Osteoporosis is a common condition worldwide, affecting millions of people. Women are more commonly affected than men, and the risk increases with age. Inflammatory reaction plays a crucial role in the expansion of osteoporosis. Osteoporosis is characterized by a gradual decline in bone density and bone tissue quality, which increases fragility and raises the risk of fractures. We scrutinized the anti-osteoporosis effect of hydroxysafflor yellow A (HYA) against glucocorticoid-induced osteoporosis (GIOP) in rats. In-silico study was carried out on EGFR receptor (PDBID: 1m17), Estrogen Alpha (PDB id: 2IOG), MTOR (PDB id: 4FA6), RANKL (PDB id: 1S55), and VEGFR2 (PDB id: 1YWN) protein. For this investigation, Sprague-Dawley (SD) rats were used, and they received an oral dose of HYA (5, 10, and 20 mg/kg, b.w.) along with a subcutaneous injection of dexamethasone (0.1 mg/kg/day) to induce osteoporosis. The biomechanical, bone parameters, antioxidant, cytokines, inflammatory, nutrients, hormones, and urine parameters were estimated. HYA treatment significantly suppressed the body weight and altered the organ weight. HYA treatment remarkably suppressed the level of alkaline phosphatase, acid phosphatase, and improved the level of bone mineral density (total, proximal, mild, and dis). HYA treatment restored the level of calcium (Ca), phosphorus (P), estradiol (E2), and parathyroid hormone near to the normal level. HYA treatment remarkably altered the level of biomechanical parameters, antioxidant, cytokines, urine, and inflammatory parameters. HYA treatment altered the level of osteoprotegerin (OPG), receptor activator of nuclear factor kappa beta (RANKL) and RANKL/OPG ratio. The result clearly showed the anti-osteoporosis effect of HYA against GIOP-induced osteoporosis in rats via alteration of antioxidant, cytokines, inflammatory, and bone protective parameters.

The potential therapeutic role of curcumin in osteoporosis treatment: based on multiple signaling pathways

Osteoporosis is a common chronic metabolic bone disease caused by disturbances in normal bone metabolism and an imbalance between osteoblasts and osteoclasts. Osteoporosis is characterized by a decrease in bone mass and bone density, leading to increased bone fragility. Osteoporosis is usually treated with medications and surgical methods, but these methods often produce certain side effects. Therefore, the use of traditional herbal ingredients for the treatment of osteoporosis has become a focus of attention and a hot topic in recent years. Curcumin, widely distributed among herbs such as turmeric, tulip, and curcuma longa, contains phenolic, terpenoid, and flavonoid components. Modern pharmacological studies have confirmed that curcumin has a variety of functions including antioxidant and anti-inflammatory properties. In addition, curcumin positively regulates the differentiation and promotes the proliferation of osteoblasts, which play a crucial role in bone formation. Multiple studies have shown that curcumin is effective in the treatment of osteoporosis as it interacts with a variety of signaling pathway targets, thereby interfering with the formation of osteoblasts and osteoclasts and regulating the development of osteoporosis. This review summarized the key signaling pathways and their mechanisms of action of curcumin in the prevention and treatment of osteoporosis and analyzed their characteristics and their relationship with osteoporosis and curcumin. This not only proves the medicinal value of curcumin as a traditional herbal ingredient but also further elucidates the molecular mechanism of curcumin's anti-osteoporosis effect, providing new perspectives for the prevention and treatment of osteoporosis through multiple pathways.

Natural Compounds for Preventing Age-Related Diseases and Cancers

Aging is a multifaceted process influenced by hereditary factors, lifestyle, and environmental elements. As time progresses, the human body experiences degenerative changes in major functions. The external and internal signs of aging manifest in various ways, including skin dryness, wrinkles, musculoskeletal disorders, cardiovascular diseases, diabetes, neurodegenerative disorders, and cancer. Additionally, cancer, like aging, is a complex disease that arises from the accumulation of various genetic and epigenetic alterations. Circadian clock dysregulation has recently been identified as an important risk factor for aging and cancer development. Natural compounds and herbal medicines have gained significant attention for their potential in preventing age-related diseases and inhibiting cancer progression. These compounds demonstrate antioxidant, anti-inflammatory, anti-proliferative, pro-apoptotic, anti-metastatic, and anti-angiogenic effects as well as circadian clock regulation. This review explores age-related diseases, cancers, and the potential of specific natural compounds in targeting the key features of these conditions.

Curcumin-loaded scaffolds in bone regeneration

In recent years, there has been a notable surge in the development of engineered bone scaffolds intended for the repair of bone defects. While autografts and allografts have traditionally served as the primary methods in bone tissue engineering, their inherent limitations have spurred the exploration of novel avenues in biomedical implant development. The emergence of bone scaffolds not only facilitates bone reconstruction but also offers a platform for the targeted delivery of therapeutic agents. There exists a pervasive interest in leveraging various drugs, proteins, growth factors, and biomolecules with osteogenic properties to augment bone formation, as the enduring side effects associated with current clinical modalities necessitate the pursuit of safer alternatives. Curcumin, the principal bioactive compound found in turmeric, has demonstrated notable efficacy in regulating the proliferation and differentiation of bone cells while promoting bone formation. Nevertheless, its utility is hindered by restricted water solubility and poor bioavailability. Strategies aimed at enhancing the solubility, stability, and bioavailability of curcumin, including formulation techniques such as liposomes and nanoparticles or its complexation with metals, have been explored. This investigation is dedicated to exploring the impact of curcumin on the proliferation, differentiation, and migration of osteocytes, osteoblasts, and osteoclasts.

Nutraceuticals and Functional Foods: A Comprehensive Review of Their Role in Bone Health

Bone health is the result of a tightly regulated balance between bone modeling and bone remodeling, and alterations of these processes have been observed in several diseases both in adult and pediatric populations. The imbalance in bone remodeling can ultimately lead to osteoporosis, which is most often associated with aging, but contributing factors can already act during the developmental age, when over a third of bone mass is accumulated. The maintenance of an adequate bone mass is influenced by genetic and environmental factors, such as physical activity and diet, and particularly by an adequate intake of calcium and vitamin D. In addition, it has been claimed that the integration of specific nutraceuticals such as resveratrol, anthocyanins, isoflavones, lycopene, curcumin, lutein, and β-carotene and the intake of bioactive compounds from the diet such as honey, tea, dried plums, blueberry, and olive oil can be efficient strategies for bone loss prevention. Nutraceuticals and functional foods are largely used to provide medical or health benefits, but there is an urge to determine which products have adequate clinical evidence and a strong safety profile. The aim of this review is to explore the scientific and clinical evidence of the positive role of nutraceuticals and functional food in bone health, focusing both on molecular mechanisms and on real-world studies.

Vascular endothelial cells-derived exosomes synergize with curcumin to prevent osteoporosis development

Osteoporosis has gradually become a major public health problem. Further elucidation of the pathophysiological mechanisms that induce osteoporosis and identification of more effective therapeutic targets will have important clinical significance. Experiments in vitro on bone marrow stem cells (BMSCs) subjected to osteogenic and adipogenic differentiation and in vivo on surgical bilateral ovariectomy (OVX) mouse models revealed that exosomes of vascular endothelial cells (EC-EXOs) can promote osteogenic differentiation of BMSCs and inhibit BMSC adipogenic differentiation through miR-3p-975_4191. Both miR-3p-975_4191 and curcumin can target tumor necrosis factor (TNF) and act synergistically to regulate BMSCs fate differentiation and delay the progression of osteoporosis. Our findings suggest that EC-EXOs may exert a synergistic effect with curcumin in reversing the progression of osteoporosis by targeting TNF via miR-3p-975_4191. Our study may provide therapeutic options and potential therapeutic targets for osteoporosis and thus has important clinical implications.

Asiatic acid prevents glucocorticoid-induced femoral head osteonecrosis via PI3K/AKT pathway

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) represents a predominant etiology of non-traumatic osteonecrosis, imposing substantial pain, restricting hip mobility, and diminishing overall quality of life for affected individuals. Centella asiatica (L.) Urb. (CA), an herbal remedy deeply rooted in traditional oriental medicine, has exhibited noteworthy therapeutic efficacy in addressing inflammation and facilitating wound healing. Drawing from CA's historical applications, its anti-inflammatory, anti-apoptotic, and antioxidant attributes may hold promise for managing GIONFH. Asiatic acid (AA), a primary constituent of CA, has been substantiated as a key contributor to its anti-apoptotic, antioxidant, and anti-inflammatory capabilities, showcasing a close association with orthopedic conditions. For the investigation of whether AA could alleviate GIONFH through suppressing oxidative stress, apoptosis, and to delve into its potential cellular and molecular mechanisms, the connection between AA and disease was analyzed through network pharmacology. DEX-induced apoptosis in rat osteoblasts and GIONFH in rat models, got utilized for the verification in vitro/vivo, on underlying mechanism of AA in GIONFH. Network pharmacology analysis reveals a robust correlation between AA and GIONFH in multiple target genes. AA has demonstrated the inhibition of DEX-induced osteoblast apoptosis by modulating apoptotic factors like BAX, BCL-2, Cleaved-caspase3, and cleaved-caspase9. Furthermore, it effectively diminishes the ROS overexpression and regulates oxidative stress through mitochondrial pathway. Mechanistic insights suggest that AA's therapeutic effects involve phosphatidylinositol 3-kinase/Protein kinase B (PI3K/AKT) pathway activation. Additionally, AA has exhibited its potential to ameliorate GIONFH progression in rat models. Our findings revealed that AA mitigated DEX-induced osteoblast apoptosis and oxidative stress through triggering PI3K/AKT pathway. Also, AA can effectively thwart GIONFH occurrence and development in rats.

Agomelatine alleviates steroid-induced osteoporosis by targeting SIRT1/RANKL/FOXO1/OPG signalling in rats

One of the major contributors to secondary osteoporosis is long-term glucocorticoid usage. Clinically used antidepressant agomelatine also has anti-inflammatory properties. Our research aimed to inspect the probable defensive effect of agomelatine against steroid-promoted osteoporosis. There were four groups of rats; group I had saline as a negative control; rats of group II had dexamethasone (0.6 mg/kg, s.c.), twice weekly for 12 weeks; rats of group III had agomelatine (40 mg/kg/day, orally), as a positive control, daily for 12 weeks; and rats of group IV had dexamethasone + agomelatine in the same previous doses combined for 12 weeks. Finally, biochemical as well as histopathological changes were evaluated and dexamethasone treatment caused osteoporosis, as evidenced by discontinuous thin cancellous bone trabeculae, minor fissures and fractures, irregular eroded endosteal surface with elevated alkaline phosphate, tartarate resistant acid phosphate (TRACP) and osteocalcin levels. Osteoprotegerin (OPG), calcium, and phosphorus levels decreased with disturbed receptor activator of nuclear factor κ B ligand (RANKL), forkhead box O1 (FOXO1), and silent information regulator 1 (SIRT1) protein expression. However, treatment with agomelatine restored the normal levels of biochemical parameters to a great extent, supported by SIRT activation with an improvement in histopathological changes. Here, we concluded that agomelatine ameliorates steroid-induced osteoporosis through a SIRT1/RANKL/FOXO1/OPG-dependent pathway.

The Therapeutic Potential of Two Egyptian Plant Extracts for Mitigating Dexamethasone-Induced Osteoporosis in Rats: Nrf2/HO-1 and RANK/RANKL/OPG Signals

The prolonged use of exogenous glucocorticoids, such as dexamethasone (Dex), is the most prevalent secondary cause of osteoporosis, known as glucocorticoid-induced osteoporosis (GIO). The current study examined the preventative and synergistic effect of aqueous chicory extract (ACE) and ethanolic purslane extract (EPE) on GIO compared with Alendronate (ALN). The phytochemical contents, elemental analysis, antioxidant scavenging activity, and ACE and EPE combination index were evaluated. Rats were randomly divided into control, ACE, EPE, and ACE/EPE MIX groups (100 mg/kg orally), Dex group (received 1.5 mg Dex/kg, Sc), and four treated groups received ACE, EPE, ACE/EPE MIX, and ALN with Dex. The bone mineral density and content, bone index, growth, turnover, and oxidative stress were measured. The molecular analysis of RANK/RANKL/OPG and Nrf2/HO-1 pathways were also evaluated. Dex causes osteoporosis by increasing oxidative stress, decreasing antioxidant markers, reducing bone growth markers (OPG and OCN), and increasing bone turnover and resorption markers (NFATc1, RANKL, ACP, ALP, IL-6, and TNF-α). In contrast, ACE, EPE, and ACE/EPE MIX showed a prophylactic effect against Dex-induced osteoporosis by modulating the measured parameters and the histopathological architecture. In conclusion, ACE/EPE MIX exerts a powerful synergistic effect against GIO by a mode of action different from ALN.

Effects of nano-micelles curcumin-based photodynamic therapy on expression of RUNX2 as an indicator of bone regeneration in orthodontic tooth movement

OBJECTIVES

The aim was to evaluate the impact of nano-micelles curcumin (NMCur) based photodynamic therapy (PDT) during compressive force application on human PDL-derived fibroblasts (HPDFs) in vitro for up to 6 days on the expression of RUNX2 as an indicator of bone development and remodeling.

MATERIALS AND METHODS

HPDFs viability during 2 g/cm2 compressive force application was investigated using membrane-impermeable DNA-binding stain propidium iodide (PI) in flow cytometry. Gene and protein expressions of RUNX2 were assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and flow cytometry, respectively, following NMCur-PDT at different concentrations of NMCur (25, 50, and 75 µM plus irradiation of 180 mW/cm2 diode laser at the wavelength of 450 ± 10 nm for 5 min) during the static compressive force of 2 g/cm2 on HPDFs via weight approach-based in-vitro loading model up to 6 days. One-way ANOVA and Tukey post hoc tests at a p-value equal to/or less than 0.05 were used to analyze the obtained data.

RESULTS

After 6 days of application of compressive force, 99.21 ± 6.12% of HPDFs were PI negative and therefore considered alive, while only 0.89 ± 0.06% of the population were PI positive and considered dead. In comparison with controls (loaded HPDFs), expression of RUNX2 gene was dose-dependent and the highest expression (14.38-fold; P < 0.01) was observed at a concentration of 75 µM NMCur following 5 min of diode laser irradiation (i.e., 75 µM NMCur-PDT) during compressive force application on day 5. The greatest and lowest upregulations of RUNX2 protein were observed in 75 µM NMCur-PDT during compressive force application on HPDFs, on day 5 (3.19-fold; P < 0.01) and day 6 (2.09-fold; P < 0.05), respectively.

CONCLUSION

NMCur-PDT during weight approach-based in-vitro loading model can promote orthodontic tooth movement by upregulating RUNX2 signaling pathway in HPDFs.

Micelle encapsulated curcumin and piperine-laden 3D printed calcium phosphate scaffolds enhance in vitro biological properties

Limitations in the current clinical management of critical-sized osseous defects have driven the need for multifunctional bone constructs. The ideal bone scaffold should possess advanced microarchitecture, well-defined pore interconnectivity, and supply biological signals, which actively guide and control tissue regeneration while simultaneously preventing post-implantation complications. Here, a natural medicine-based localized drug delivery from 3D printed scaffold is presented, which offers controlled release of curcumin, piperine from nano-sized polymeric micelles, and burst release of antibacterial carvacrol from the coating endowing the scaffold with their distinct, individual biological properties. This functionalized scaffold exhibits improved osteoblast (hFOB) cell attachment, 4-folds higher hFOB proliferation, and 73% increased hFOB differentiation while simultaneously providing cytotoxicity towards osteosarcoma cells with 61% lesser viability compared to control. In vitro, early tube formation (p < 0.001) indicates that the scaffolds can modulate the endothelial cellular network, critical for faster wound healing. The scaffold also exhibits 94% enhanced antibacterial efficacy (p < 0.001) against gram-positive Staphylococcus aureus, the main causative bacteria for osteomyelitis. Together, the multifunctional scaffolds provide controlled delivery of natural biomolecules from the nano-sized micelle-loaded 3D printed matrix for significant improvement in osteoblast proliferation, endothelial formation, osteosarcoma, and bacterial inhibition, guiding better bone regeneration for post-traumatic defect repair.

Protective effects of curcumin against osteoporosis and its molecular mechanisms: a recent review in preclinical trials

Osteoporosis (OP) is one of the most common metabolic skeletal disorders and is commonly seen in the elderly population and postmenopausal women. It is mainly associated with progressive loss of bone mineral density, persistent deterioration of bone microarchitecture, and increased fracture risk. To date, drug therapy is the primary method used to prevent and treat osteoporosis. However, long-term drug therapy inevitably leads to drug resistance and specific side effects. Therefore, researchers are constantly searching for new monomer compounds from natural plants. As a candidate for the treatment of osteoporosis, curcumin (CUR) is a natural phenolic compound with various pharmacological and biological activities, including antioxidant, anti-apoptotic, and anti-inflammatory. This compound has gained research attention for maintaining bone health in various osteoporosis models. We reviewed preclinical and clinical studies of curcumin in preventing and alleviating osteoporosis. These results suggest that if subjected to rigorous pharmacological and clinical trials, naturally-derived curcumin could be used as a complementary and alternative medicine for the treatment of osteoporosis by targeting osteoporosis-related mechanistic pathways. This review summarizes the mechanisms of action and potential therapeutic applications of curcumin in the prevention and mitigation of osteoporosis and provides reference for further research and development of curcumin.

Oxidative Stress, Reductive Stress and Antioxidants in Vascular Pathogenesis and Aging

This review is focused on the mechanisms that regulate health, disease and aging redox status, the signal pathways that counteract oxidative and reductive stress, the role of food components and additives with antioxidant properties (curcumin, polyphenols, vitamins, carotenoids, flavonoids, etc.), and the role of the hormones irisin and melatonin in the redox homeostasis of animal and human cells. The correlations between the deviation from optimal redox conditions and inflammation, allergic, aging and autoimmune responses are discussed. Special attention is given to the vascular system, kidney, liver and brain oxidative stress processes. The role of hydrogen peroxide as an intracellular and paracrine signal molecule is also reviewed. The cyanotoxins β-N-methylamino-l-alanine (BMAA), cylindrospermopsin, microcystins and nodularins are introduced as potentially dangerous food and environment pro-oxidants.

Understanding the mechanistic potential of plant based phytochemicals in management of postmenopausal osteoporosis

Postmenopausal osteoporosis, an epidemic disorder is defined as a loss in bone mineral density and a greater possibility of fractures in older women. It is a multifactorial disease under the control of various genetic, hormonal, and environmental factors. Insufficiency of estrogen hormone, leads to postmenopausal osteoporosis. Hormone replacement therapy (HRT), despite being the most effective treatment, it is associated with the risk of breast cancer and cardiovascular disorders. This review seeks to compile the most recent information on medicinal plants and natural compounds used to treat and prevent postmenopausal osteoporosis. Furthermore, the origin, chemical constituents and the molecular mechanisms responsible for this therapeutic and preventive effect are also discussed. Literature research was conducted using PubMed, Science direct, Scopus, Web of Science, and Google Scholar. Different plant extracts and pure compounds exerts their antiosteoporotic activity by inhibition of RANKL and upregulation of OPG. RANKL signaling regulates osteoclast formation, characterized by increased bone turnover and osteoprotegrin is a decoy receptor for RANKL thereby preventing bone loss from excessive resorption. In addition, this review also includes the chemical structure of bioactive compounds acting on NFκB, TNF α, RUNX2. In conclusion, we propose that postmenopausal osteoporosis could be prevented or treated with herbal products.

Diosmin mitigates dexamethasone-induced osteoporosis in vivo: Role of Runx2, RANKL/OPG, and oxidative stress

Secondary osteoporosis is commonly caused by long-term intake of glucocorticoids (GCs), such as dexamethasone (DEX). Diosmin, a natural substance with potent antioxidant and anti-inflammatory properties, is clinically used for treating some vascular disorders. The current work targeted exploring the protective properties of diosmin to counteract DEX-induced osteoporosis in vivo. Rats were administered DEX (7 mg/kg) once weekly for 5 weeks, and in the second week, vehicle or diosmin (50 or 100 mg/kg/day) for the next four weeks. Femur bone tissues were collected and processed for histological and biochemical examinations. The study findings showed that diosmin alleviated the histological bone impairments caused by DEX. In addition, diosmin upregulated the expression of Runt-related transcription factor 2 (Runx2) and phosphorylated protein kinase B (p-AKT) and the mRNA transcripts of Wingless (Wnt) and osteocalcin. Furthermore, diosmin counteracted the rise in the mRNA levels of receptor activator of nuclear factor-kB ligand (RANKL) and the reduction in osteoprotegerin (OPG), both were induced by DEX. Diosmin restored the oxidant/antioxidant equilibrium and exerted significant antiapoptotic activity. The aforementioned effects were more pronounced at the dose level of 100 mg/kg. Collectively, diosmin has proven to protect rats against DEX-induced osteoporosis by augmenting osteoblast and bone development while hindering osteoclast and bone resorption. Our findings could be used as a stand for recommending supplementation of diosmin for patients chronically using GCs.

Anti-Oxidant Multi-Functionalized Materials: Strontium-Substituted Monetite and Brushite as Delivery Systems for Curcumin

Curcumin has numerous biological activities and pharmaceutical applications related to its ability to inhibit reactive oxygen species. Herein, strontium-substituted monetite (SrDCPA) and strontium-substituted brushite (SrDCPD) were synthesized and further functionalized with curcumin with the aim to develop materials that combine the anti-oxidant properties of the polyphenol, the beneficial role of strontium toward bone tissue, and the bioactivity of calcium phosphates. Adsorption from hydroalcoholic solution increases with time and curcumin concentration, up to about 5-6 wt%, without affecting the crystal structure, morphology, and mechanical response of the substrates. The multi-functionalized substrates exhibit a relevant radical scavenging activity and a sustained release in phosphate buffer. Cell viability, morphology, and expression of the most representative genes were tested for osteoclast seeded in direct contact with the materials and for osteoblast/osteoclast co-cultures. The materials at relatively low curcumin content (2-3 wt%) maintain inhibitory effects on osteoclasts and support the colonization and viability of osteoblasts. The expressions of Alkaline Phosphatase (ALPL), collagen type I alpha 1 chain (COL1A1), and osteocalcin (BGLAP) suggest that curcumin reduces the osteoblast differentiation state but yields encouraging osteoprotegerin/receptor activator for the NFkB factor ligand (OPG/RANKL) ratio.

Long non-coding RNA telomerase RNA elements improve glucocorticoid-induced osteoporosis by EZH2 to regulate DKK1

BACKGROUND

Glucocorticoid-induced osteoporosis is the most common secondary cause of osteoporosis, which increases the risk of fracture. Long non-coding RNA telomerase RNA elements (TERC) has been proven to be closely related to osteoporosis. However, the role of TERC in glucocorticoid-induced osteoporosis and its underlying molecular mechanism remains unclear.

METHODS

The in vitro model of osteoporosis was established after bone marrow mesenchymal stem cells (BMSCs) were exposed to dexamethasone (DEX). The cell viability, alkaline phosphatase (ALP) activity and mineralized nodules of BMSCs were evaluated. The messenger RNA and protein levels were detected by quantitative real-time polymerase chain reaction and Western blot. The interaction between TERC, enhancer of zeste homolog 2 (EZH2) and dickkopf-1 (DKK1) was confirmed by chromatin immunoprecipitation and RNA immunoprecipitation assays.

RESULTS

Bone marrow mesenchymal stem cells were isolated, identified and induced osteogenic differentiation. The findings showed that the levels of osteogenic marker genes, including ALP, Runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) in BMSCs were increased dependent on the osteogenic induction time. Similarly, TERC was significantly increased, but DKK1 was significantly decreased during BMSC osteogenic differentiation. Functional research showed that TERC overexpression promoted cell viability, ALP activity and mineralized nodules of BMSCs and increased the levels of osteogenic differentiation-related genes (ALP, RUNX2 and OCN), and TERC overexpression increased EZH2 protein level. Moreover, the decrease of cell viability, ALP activity and mineralized nodules induced by DEX was reversed by TERC overexpression. Furthermore, TERC inhibited DKK1 expression by promoting the histone modification of DKK1, and TERC overexpression alleviated DEX suppressed osteogenic differentiation of BMSCs by interaction with EZH2 to regulate DKK1.

CONCLUSION

Our findings illustrated that TERC overexpression alleviated DEX-induced osteoporosis by recruiting EZH2 to regulate DKK1. Our research provided a novel direction for the treatment of glucocorticoid-induced osteoporosis.

Methods to Improve the Solubility of Curcumin from Turmeric

Turmeric is a strong-taste component of spices characteristic of Indian cuisine. It is obtained from the turmeric rhizome (Curcumae longae rhizoma) and has been used for thousands of years not only for culinary purposes, but also for medicinal purposes. It contains a group of organic compounds called curcuminoids. Curcumin is the main representative of this group of compounds which is also most frequently studied. In recent years, bioactive curcuminoids (including curcumin in the first place) have become more and more popular due to a wide spectrum of their biological activity. The anticancer, antibacterial, anti-inflammatory, and antiaging effects of curcumin have been confirmed by numerous in vitro and in vivo studies, as well as in clinical trials. However, an obstacle to simple, clinical application of curcumin is its poor bioavailability (which is due to its hydrophobic nature) and its very weak water solubility. Therefore, many scientists are working on improving the solubility of curcumin in water, which is the topic of the present article. Attempts have been made to combine curcumin with nanoparticles (polysaccharide or silica). Nanosuspensions or complexes with cyclodextrins are also considered. A promising direction is the search for new polymorphic varieties as well as obtaining cocrystals with curcumin which are characterized by better water solubility.

Graphene oxide reinforced SrHAP composite as a drug carrier in bone regeneration

Strontium substituted HAP (SrHAP), with a 10 mol% substitution, was mineralized on increasing weight percentages of graphene oxide (2, 4 and 6). The GS composites were comprehensively characterized for drug delivery in bone reconstruction. The formation of SrHAP was verified by XRD and FT-IR results. The apatite crystallization was influenced by graphene oxide content and strontium. The EDS results confirmed the presence of strontium and HR-SEM depicted rod shape apatite, of length between 58 and 135 nm, uniformly embedded on graphene oxide. The reinforcement of graphene oxide increased the surface area, porosity, microhardness (upto 0.59 GPa), protein adsorption (upto 18.16 μg/mg), water uptake and degradation properties. Also, the increase in graphene oxide fraction significantly enhanced the curcumin encapsulation efficiency (upto 80.16%) and the drug release was considerably retarded over SrHAP. The in vitro studies using human osteoblast-like MG-63 cells demonstrated that curcumin-loaded composite was biocompatible and promoted proliferation, differentiation and matrix mineralization. The results highlight the combinational therapy of osteogenic ion (strontium) and osteogenic drug (curcumin) as a promising platform in bone tissue engineering.

Antiosteoporosis and bone protective effect of nimbolide in steroid-induced osteoporosis rats

BACKGROUND

Osteoporosis is a metabolic, hereditary, progressive disease characterized by unusual bone production across the skeleton and a loss the bone tissue microstructure and mass. In this experimental study, we scrutinized the antiosteoporosis effect of nimbolide against glucocorticoid (GCs) induced osteoporosis in rats.

METHODS

Swiss albino female rats were employed for the current experiment study and the rats were divided into different groups. Dexamethasone (0.1 mg/kg/day) was used for induction the osteoporosis and the rats were received the different doses of nimbolide (2.5, 5, and 7.5 mg/kg) for the estimation of bone protective effects. The body weight was estimated (initially and finally). Hormones, bone metabolic markers, bone turnover markers, bone structure, biomechanical, histomorphometric dynamic, biochemical markers, and histomorphometric static parameters were analyzed.

RESULTS

The body weight of GCs group rats considerably suppressed and nimbolide treatment remarkably improved the body weight. Nimbolide treated group exhibited the enhancement of bone metabolic, bone structure markers, and histomophometric dynamic markers, which was suppressed during the GCs-induced osteoporosis. GCs-induced osteoporosis rats exhibited the enhancement of procollagen type 1 C-terminal propeptide (P1CP), carboxy-terminal crosslinked telopeptide of type 1 collagen (CTX-1), Dickkopf-1 (DKK1), tartrate-resistant acid phosphatase 5b (TRACP 5b), and suppressed the level of bone alkaline phosphatase (BAP), which was reversed by the nimbolide treatment. Nimbolide treatment remarkably improved the level of estradiol and suppressed the level of parathyroid hormone (PTH), which was altered during the osteoporosis. Nimbolide treatment significantly (p < 0.001) improved the level of calcium, magnesium, and phosphorus in the serum and bone tissue. Nimbolide treatment also altered the level of bone metabolic markers and suppressed the level of inflammatory cytokines.

CONCLUSION

Based on the findings, we may conclude that nimbolide has antiosteoporosis properties via balancing the bone mass and improving vitamin and hormone levels.

Evaluation of quaternization effect on chitosan-HAP composite for bone tissue engineering application

This study attempts to improve the aqueous solubility of chitosan and utilizes it in the fabrication of composites with hydroxyapatite (HAP). The composites were evaluated as a curcumin delivery vehicle for bone regeneration. The chitosan was modified by quaternization, with a quaternization degree of 5 % for low quaternized chitosan (LQC) and 11 % for high quaternized chitosan (HQC). The modified chitosan, at alkaline pH 11, facilitated in situ HAP growth and formed LQC-HAP and HQC-HAP composites. The quaternization weakens intermolecular hydrogen bonds, facilitates interaction with the apatite precursor ions and promotes the growth of HAP. The modification significantly improved drug encapsulation (2.6 fold) but at the cost of a slight decrease in mechanical strength and increase in drug release. The in vitro studies with human osteoblast-like MG-63 cells established that the curcumin-loaded composites, LQC-HAP-C and HQC-HAP-C are biocompatible, encourage proliferation and promote a 2-fold increase in calcium mineralization over drug-free composites. The study exemplifies the reciprocity between quaternization degree and drug load/release properties and also illustrates that the magnitude of the latter reflects bioactivity. Thus, the quaternized chitosan-based HAP composite with tailorable bio-physicochemical properties becomes an interesting drug delivery system in bone regeneration.

Long noncoding RNA TRG-AS1 protects against glucocorticoid-induced osteoporosis in a rat model by regulating miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis

The long-term treatment of glucocorticoids is a common cause of osteoporosis (OP). This study concentrated on inquiring into the regulatory role and potential mechanisms of TRG-AS1 on dexamethasone (Dex)-induced OP in rats. We adopted Dex to treat rat osteoblasts and rats to simulate in-vitro and in-vivo OP models, respectively. Gain-of-function assays of TRG-AS1, miR-802 and CAB39 were constructed in rat osteoblasts to make certain the influence of TRG-AS1, miR-802 and CAB39 on differentiation, proliferation and apoptosis of rat osteoblasts. TRG-AS1 and CAB39 were down-regulated in the Dex-induced OP model in rats, in contrast to miR-802. Overexpression of TRG-AS1 restrained Dex-induced inhibition of osteogenic differentiation, promoted CAB39/AMPK/SIRT-1 and inhibited NF-κB, while overexpression of miR-802 bridled the inhibitory effect of TRG-AS1 on OP. miR-802 was targeted by TRG-AS1, and inhibited CAB39. Inhibition of either AMPK or SIRT-1 abated the osteogenic differentiation-promoting effect of CAB39. Animal experiments displayed that overexpressing TRG-AS1 alleviated Dex-induced OP in rats. In conclusion, up-regulation of TRG-AS1 protected against glucocorticoid-induced OP in rats by modulating the miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.

Phoenix dactilyfera L. Pits Extract Restored Bone Homeostasis in Glucocorticoid-Induced Osteoporotic Animal Model through the Antioxidant Effect and Wnt5a Non-Canonical Signaling

Oxidative stress associated with long-term glucocorticoids administration is a route through which secondary osteoporosis can be developed. The therapeutic potential of Phoenix dactilyfera L. pits is offered by their balanced, valuable and diverse phytochemical composition providing protective potential against oxidative reactions, making it a good candidate to treat glucocorticoid-induced osteoporosis (GIO). This study evaluates the possible anti-osteoporotic effect of date pit extract (DPE) against dexamethasone (DEXA)-induced osteoporosis. Male rats were allocated into three control groups, which received saline, low and high doses of DPE (150 and 300 mg/kg/day), respectively. Osteoporosis-induced groups that received DEXA (1 mg/kg/day) were divided into DEXA only, DPE (2 doses) + DEXA, and ipriflavone + DEXA. Femoral bone minerals density and bone mineral content, bone oxidative stress markers, Wnt signaling, osteoblast and osteoclast differentiation markers, and femur histopathology were evaluated. DPE defeated the oxidative stress, resulting in ameliorative changes in Wnt signaling. DPE significantly reduced the adipogenicity and abolished the osteoclastogenic markers (RANKL/OPG ratio, ACP, TRAP) while enhancing the osteogenic differentiation markers (Runx2, Osx, COL1A1, OCN). In Conclusion DPE restored the balanced proliferation and differentiation of osteoclasts and osteoblasts precursors. DPE can be considered a promising remedy for GIO, especially at a low dose that had more potency.

Phosphatidylserine liposomes containing curcumin inhibit bone loss in osteoporotic rats: A possible synergy through a common signaling pathway

The present study aimed to investigate the effect of phosphatidylserine liposomes containing curcumin (PSLs-Cur) on the development of osteoporosis induced by glucocorticoids (GCs) in the rat model. PSL-Cur, phosphatidylserine (PSL), curcumin (Cur), and alendronate (AL) drugs as a positive control were administrated orally to evaluate the beneficial effects of 3-week treatments on osteoporotic rats. The biochemical and biomechanical properties of bone parameters as well as gene expression were evaluated in treated rats. Moreover, histomorphometric examinations were performed on the bone tissues of the animals. The results revealed that PSL-Cur oral administration caused a significant improvement in serum markers, mechanical strength, and OPG gene expression rather than PSL or Cur administration in osteoporotic rats. Also, PSL-Cur significantly increased the thickness and volume of cortical and trabecular bone mass in comparison with the untreated osteoporotic group. The results of this study indicated that PSL-Cur had a more inhibitory effect on bone loss induced by GCs compared to AL standard drug. Our findings suggested that PSL-loaded Cur may be an appropriate alternative therapy for glucocorticoid-induced osteoporosis. PRACTICAL APPLICATIONS: Osteoporosis is one of the most serious metabolic chronic diseases that causes fragile bone due to decreased mineral density and microarchitectural deterioration in humans. The osteoprotective effects of curcumin and phosphatidylserine, as a food spice and supplementary diet, respectively, have been shown, previously. However, the low bioavailability of curcumin (Cur) due to its poor absorption, rapid metabolism, and fast systemic elimination, limits its benefits. This deficit can be modified with phosphatidylserine liposome (PSL) formulation that facilitates the gastrointestinal delivery of Cur. Moreover, PSL is known as an osteoprotective agent that may make synergy effect with Cur against GC-induced osteoporosis. In this study, daily oral administration of phosphatidylserine liposomes containing curcumin (PSL-Cur) for 3 weeks, considerably improved biochemical, biomechanical, and gene expression of bone parameters in the treated animals subjected to osteoporosis. PSL-Cur can significantly increase the thickness and volume of cortical and trabecular bone mass as well as the mechanical bone strength in animals. Experimental findings proposed PSL-Cur consumption as a proper and safe supplementary medication in the controlling of bone loss in patients with a high risk of osteoporosis.

Bioperformance Studies of Biphasic Calcium Phosphate Scaffolds Extracted from Fish Bones Impregnated with Free Curcumin and Complexed with β-Cyclodextrin in Bone Regeneration

Fish bones are a natural calcium phosphate (CaP) sources used in biomaterials production for bone regeneration. CaP scaffolds can be enriched with other substances with biological activity to improve bone repair. This study aimed to evaluate the physicochemical properties and bone regeneration potential of biphasic calcium phosphate (BCP) scaffolds impregnated with free curcumin (BCP-CL) or complexed with β-cyclodextrin (BCP-CD) compared to BCP scaffolds. Rietveld’s refinement showed that BCP is composed of 57.2% of HAp and 42.8% of β-TCP and the molar ratio of Ca/P corresponds to 1.59. The scaffolds presented porosity (macro and microporosity) of 57.21%. Apatite formation occurred on the BCP, BCP-CL, and BCP-CD surface, in vitro, in SBF. Micro-Raman technique showed a reduction in the dissolution rate of β-TCP in the curcumin-impregnated scaffolds over time, and in vivo studies on critical-size defects, in rat calvaria, had no additional regenerative effect of BCP-CL and BCP-CD scaffolds, compared to BCP scaffolds. Despite this, the study showed that curcumin impregnation in BCP scaffolds prolongs the release of the β-TCP phase, the BCP- phase with the higher osteoinductive potential, representing an advantage in tissue engineering.

Benzofuran pyran hybrid prevents glucocorticoid induced osteoporosis in mice via modulation of canonical Wnt/β-catenin signaling

Glucocorticoid induced osteoporosis (GIOP) is the second most leading cause of osteoporosis. We have identified a compound, a benzofuran pyran hybrid compound 4e that has osteogenic potential and we wanted to assess its efficacy in GIOP in male mice. We assessed the effect of dexamethasone and compound 4e on primary osteoblasts using various cell based and immunofluorescence assays. For in vivo studies we administered methylprednisolone and compound 4e as a prophylactic measure in male Balb/c mice for 28 days and then evaluated the effect on bone microarchitecture by microCT, bone formation by histology along with clinically relevant bone markers. Compound 4e preserved osteoblast differentiation as evident by higher ALP positive cells and mineralization in compound treated groups. Compound 4e also increased the expression of osteogenic genes. This compound guarded β-catenin expression both in vitro and in vivo as confirmed by western blot and immunofluorescence assays. This led to the preservation of bone microarchitecture and cortical thickness at 2.5 mg kg⁻¹ and 5 mg kg⁻¹ doses. Further compound 4e enhanced bone formation rate and regulated osteocyte death. The osteogenic potential of compound 4e was reflected by an increased level of serum marker osteocalcin and decreased levels of SOST and CTX-I. Overall, Compound 4e is able to overcome the catabolic effect of dexamethasone on bone by targeting the canonical WNT/β-catenin signaling as evidenced by both in vitro and in vivo studies.

Total Flavonoids of Drynariae Rhizoma Improve Glucocorticoid-Induced Osteoporosis of Rats: UHPLC-MS-Based Qualitative Analysis, Network Pharmacology Strategy and Pharmacodynamic Validation

BACKGROUND

Glucocorticoid-induced osteoporosis (GIOP) is a common form of secondary osteoporosis caused by the protracted or a large dosage of glucocorticoids (GCs). Total flavonoids of Drynariae rhizoma (TFDR) have been widely used in treating postmenopausal osteoporosis (POP). However, their therapeutic effects and potential mechanism against GIOP have not been fully elucidated.

METHODS

Ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESIQ-TOF-MS) experiments were performed for qualitative analysis. We performed hematoxylin-eosin (HE) staining and microcomputed tomography (micro-CT) analysis to detect the changes in bone microstructure. The changes in biochemical parameters in the serum samples were determined by performing an enzyme-linked immunosorbent assay (ELISA). The prediction results of network pharmacology were verified via quantitative real-time polymerase chain reaction (qRT-PCR) to elucidate the potential mechanism of TFDR against GIOP.

RESULTS

A total of 191 ingredients were identified in vitro and 48 ingredients in vivo. In the in-vivo experiment, the levels of the serum total cholesterol (TC), the serum triglyceride (TG), Leptin (LEP), osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein-2 (BMP-2), propeptide of type I procollagen (PINP), tartrate-resistant acid phosphatase (TRACP) and type-I collagen carboxy-terminal peptide (CTX-1) in the TFDR group significantly changed compared with those in the GIOP group. Moreover, the TFDR group showed an improvement in bone mineral density and bone microstructure. Based on the results of network pharmacology analysis, 67 core targets were selected to construct the network and perform PPI analysis as well as biological enrichment analysis. Five of the targets with high "degree value" had differential gene expression between groups using qRT-PCR.

CONCLUSION

TFDR, which may play a crucial role between adipose metabolism and bone metabolism, may be a novel remedy for the prevention and clinical treatment of GIOP.

Effect of turmeric extract on bone healing in an experimental model of femoral bone fracture

Objective

Following bone trauma, several factors participate in making a balance between the activity of osteoblasts and osteoclasts. The receptor activator of nuclear factor kappa B ligand (RANKL), receptor activator of nuclear factor kappa B (RANK), and osteoprotegerin (OPG) molecules play critical roles in the healing process via regulation of osteoclasts function. Turmeric is suggested to have an anti-osteogenic potential; however, its effect on accelerating bone healing has not been adequately studied. Here, we used a rat model of femur fracture to explore the effect of treatment with turmeric extract on the bone repair and the expression of RANK, RANKL, and OPG molecules.

Materials and Methods

Eight rats were subjected to surgery, randomly divided into two groups, and treated orally with turmeric (200 mg/kg), or olive oil. Four oil-treated rats without bone fracture were used as control group. After six weeks of treatment, the femurs of animals were examined for radiological, histological, and gene expression analysis.

Results

X-ray radiography showed thicker callus and a more obscure fracture line in the turmeric group. Furthermore, higher osteoblast percentages but no osteoclasts were observed in turmeric-treated animals, representing better repair of bone in the fracture site. Also, real-time analyses showed that treatment with turmeric reduced RANK and RANKL expression (p<0.0001) and lowered RANKL/OPG ratio (p=0.01) in femoral bone tissue.

Conclusion

Our findings indicated the turmeric ability to facilitate bone hemostasis and optimize the expression of key markers involved in the bone metabolism.

Antiosteoporosis and bone protective effect of dieckol against glucocorticoid-induced osteoporosis in rats

BACKGROUND

Glucocorticoids (GCs) induce osteoporosis, which results in fractures in the bond, causing significant morbidity. In the conducted study, we examined the antiosteoporosis effect of dieckol against GC-induced osteoporosis in rats.

METHODS

Sprague-Dawley (SD) rats were used for the current study and dexamethasone (2.5 mg/kg) induced osteoporosis in the rats that received the dieckol (test) and alendronate (standard) for 20 weeks. Bone turnover parameters, microCT, antioxidant, inflammatory cytokines, nutrient, and hormones parameters.

RESULTS

Dieckol noticeably suppressed the body weight and boosted the uterine and vagina weight. Dieckol considerably altered the level of trabecular number (Tb. N), the bone volume to total volume (BV/TV), trabecular separation (Tb.Sp), bone surface to bone volume (BS/BV), and t​r​a​b​e​c​u​l​a​r thickness (Tb.Th). Dieckol noticeably (P < 0.001) elevated the level of osteocalcin (OC) and alleviated the level of bone Gla protein (BGP), acid phosphatase (ACP), alkaline phosphatase (ALP), and β-CTx. Dieckol markedly boosted the level of malondialdehyde (MDA) and suppressed the level of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) along with the suppression of inflammatory cytokines like TNF-α, IL-1β, and IL-6. Dieckol remarkably increased the level of calcium, potassium, magnesium, and 25 (OH) vitamin D. Dieckol substantially (P < 0.001) boosted the level of estradiol and alleviated the level of parathyroid hormone and tartrate-resistant acid phosphatase (TRAP). Dieckol also suppressed the level of receptor activator of nuclear factor κB ligand (RANKL) and boosted the level of osteoprotegerin (OPG).

CONCLUSION

Taken together, our data suggest that dieckol demonstrated the anti-osteoporosis effect against GC-induced osteoporosis in rats.

HO-1 in Bone Biology: Potential Therapeutic Strategies for Osteoporosis

Osteoporosis is a prevalent bone disorder characterized by bone mass reduction and deterioration of bone microarchitecture leading to bone fragility and fracture risk. In recent decades, knowledge regarding the etiological mechanisms emphasizes that inflammation, oxidative stress and senescence of bone cells contribute to the development of osteoporosis. Studies have demonstrated that heme oxygenase 1 (HO-1), an inducible enzyme catalyzing heme degradation, exhibits anti-inflammatory, anti-oxidative stress and anti-apoptosis properties. Emerging evidence has revealed that HO-1 is critical in the maintenance of bone homeostasis, making HO-1 a potential target for osteoporosis treatment. In this Review, we aim to provide an introduction to current knowledge of HO-1 biology and its regulation, focusing specifically on its roles in bone homeostasis and osteoporosis. We also examine the potential of HO-1-based pharmacological therapeutics for osteoporosis and issues faced during clinical translation.

Effect of Intermittent Fasting on Glucose Homeostasis and Bone Remodeling in Glucocorticoid-Induced Osteoporosis Rat Model

Background

The present study examined the effect of intermittent fasting (IF) on bone mineral content (BMC) and bone mineral density (BMD) and the markers of bone remodeling in a glucocorticoid-induced osteoporosis (GIO) rat model.

Methods

Forty male rats were allocated to 4 groups (N=10 per group): control group of normal rats; control+IF group (normal rats subjected to IF for 16–18 hr daily for 90 days); dexamethasone (DEX) group: (DEX [0.5 mg i.p.] for 90 days); and DEX+IF group (DEX and IF for 90 days). By the end of the experiment, BMD and BMC in the right tibia were measured. Serum levels of the following were measured: glucose; insulin; triglycerides (TGs); total cholesterol; parathyroid hormone (PTH); osteoprotegerin (OPG); receptor activator of nuclear factor-κB (RANK); bone-resorbing cytokines, including bone deoxypyridinoline (DPD), N-terminal telopeptide of collagen type I (NTX-1), and tartrate-resistant acid phosphatase 5b (TRAP-5b); and bone-forming cytokines, including alkaline phosphatase (ALP) and osteocalcin (OC).

Results

DEX administration for 90 days resulted in significantly increased serum levels of glucose, insulin, TGs, cholesterol, PTH, OPG, DPD, NTX-1, and TRAP-5b and significantly decreased BMD, BMC, and serum levels of RANK, OC, and ALP (all P<0.05). IF for 90 days significantly improved all these parameters (all P<0.05).

Conclusions

IF corrected GIO in rats by inhibiting osteoclastogenesis and PTH secretion and stimulating osteoblast activity.

Osteoprotective Effect of Enamel Matrix Derivatives on the Regeneration of Mandibular Defects in Experimentally Glucocorticoid-Induced Osteoporosis

Purpose

Osteoporosis is a progressive systematic skeletal illness characterized by low bone mineral density and susceptibility to fracture caused by bone resorption. Aim of the Study. This study intended to evaluate the possible role of emdogain in combination with calcitonin on the healing of surgically induced mandibular defects performed on osteoporotic rats.

Materials and Methods

Forty healthy female white albino rats were included in this study and divided into four groups. In group I (negative control), 10 rats received a vehicle injection after which a unilateral mandibular defect was created in each rat of all groups. Three groups were subjected to induction of osteoporosis by subcutaneous injection of 0.1 mg/kg/day dexamethasone for 60 days. In group II, rats were kept without treatment. In group III, rats were treated with daily intramuscular injection of 2.5 IU/kg of synthetic salmon calcitonin. In group IV, rats were handled as group III, and the created cavity was filled with emdogain. Rats were euthanized at 2nd and 4th week postsurgically. Hematoxylin and eosin, Masson's trichrome, NF-κB (nuclear factor of activated B cells), and immunohistochemical stains were used, followed by statistical analysis.

Results

Group I showed normal stages of bone defects healing. Group II revealed the formation of granulation tissue with dilated blood vessels, while groups III and IV showed enhanced bone healing and proper collagen fibers. The percentage area of newly formed collagen fibers was significantly higher in group IV at 2nd week (13.96 ± 0.020%) and 4th week (16.95 ± 0.024%) than in group II (8.75 ± 0.015% and 10.29 ± 0.015%, respectively) and group III (12.93 ± 0.015% and 14.61 ± 0.021%, respectively), but was lower than that in group I (15.75 ± 0.015% and 17.49 ± 0.015%, respectively).

Conclusion

The local application of emdogain combined with systemically injected calcitonin improves bone healing in surgically induced bone defects in osteoporotic rats.

Kaempferol Ameliorates the Inhibitory Activity of Dexamethasone in the Osteogenesis of MC3T3-E1 Cells by JNK and p38-MAPK Pathways

Kaempferol has been reported to exhibit beneficial effect on the osteogenic differentiation in mesenchymal stem cells (MSC) and osteoblasts. In our previous study, dexamethasone (DEX) demonstrated inhibitory effect on MC3T3-E1 cells differentiation. In this study, we mainly explored the protective effect of kaempferol on the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells. We found that kaempferol ameliorated the proliferation inhibition, cell cycle arrest, and cell apoptosis and increased the activity of alkaline phosphatase (ALP) and the mineralization in DEX-treated MC3T3-E1 cells. Kaempferol also significantly enhanced the expression of osterix (Osx) and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells treated with DEX. In addition, kaempferol attenuated DEX-induced reduction of cyclin D1 and Bcl-2 expression and elevation of p53 and Bax expression. Kaempferol also activated JNK and p38-MAPK pathways in DEX-treated MC3T3-E1 cells. Furthermore, kaempferol improved bone mineralization in DEX-induced bone damage in a zebrafish larvae model. These data suggested that kaempferol ameliorated the inhibitory activity of DEX in the osteogenesis of MC3T3-E1 cells by activating JNK and p38-MAPK signaling pathways. Kaempferol exhibited great potentials in developing new drugs for treating glucocorticoid-induced osteoporosis.

Effects of Curcumin on Aging: Molecular Mechanisms and Experimental Evidence

Aging is characterized by a progressive inability to maintain homeostasis, self-repair, renewal, performance, and fitness of different tissues throughout the lifespan. Senescence is occurring following enormous intracellular or extracellular stress stimuli. Cellular senescence serves as an antiproliferative process that causes permanent cell cycle arrest and restricts the lifespan. Senescent cells are characterized by terminal cell cycle arrest, enlarged lysosome, and DNA double-strand breaks as well as lipofuscin granularity, senescence-associated heterochromatin foci, and activation of DNA damage response. Curcumin, a hydrophobic polyphenol, is a bioactive chemical constituent of the rhizomes of Curcuma longa Linn (turmeric), which has been extensively used for the alleviation of various human disorders. In addition to its pleiotropic effects, curcumin has been suggested to have antiaging features. In this review, we summarized the therapeutic potential of curcumin in the prevention and delaying of the aging process.

Targeting Wnt signaling pathway by polyphenols: implication for aging and age-related diseases

Age is an important risk factor for different diseases. The same mechanisms that promote aging are involved in the development and progression of age-associated diseases. Polyphenols are organic compounds found in fruits and vegetables. Due to their beneficial properties (e.g. antioxidant and anti-inflammatory), polyphenols have been extensively used for treating chronic diseases. To exert their functions, polyphenols target various molecular mechanisms and signaling pathways, such as mTOR, NF-κB, and Wnt/β-catenin. Wnt signaling is a critical pathway for developmental processes. Besides, dysregulation of this signaling pathway has been observed in various diseases. Several investigations have been conducted on Wnt inhibitors at pre-clinical stages, showing promising results. Herein, we review the studies dealing with the role of polyphenols in targeting the Wnt signaling pathways in aging processes and age-associated diseases, including cancer, diabetes, Alzheimer's disease, osteoporosis, and Parkinson's disease.

Non-flavonoid polyphenols in osteoporosis: preclinical evidence

The development of progressive osteopenia and osteoporosis (OP) is due to the imbalance between bone resorption and bone formation, determining a lower bone resistance, major risks of fractures, with consequent pain and functional limitations. Flavonoids, a class of polyphenols, have been extensively studied for their therapeutic activities against bone resorption, but less attention has been given to a whole series of molecules belonging to the polyphenolic compounds. However, these classes have begun to be studied for the treatment of OP. In this systematic review, comprehensive information is provided on non-flavonoid polyphenolic compounds, and we highlight pathways implicated in the action of these molecules that act often epigenetically, and their possible use for OP treatment and prevention.

Betel leaf extract and its major component hydroxychavicol promote osteogenesis and alleviate glucocorticoid-induced osteoporosis in rats

Piper betle leaves possess several ethnomedicinal properties and are immensely used in traditional medicinal practices in regions of Asian and African subcontinents. However, their effects in treating skeletal complications are least known. In this study, we evaluated cellular and molecular effects of betel leaf extract (BLE) and its major phytoconstituent, hydroxychavicol (HCV) in promoting osteogenesis in vitro and alleviating glucocorticoid induced osteoporosis (GIO) in vivo. Both BLE and HCV markedly stimulated osteoblast differentiation of C3H10T1/2 cells with increased expression of RUNX2 and osteopontin through the GSK-3β/β-catenin-signaling pathway. Also, oral administration of BLE and HCV in GIO rats resulted in restoration of bone mass and tissue microarchitecture. Thus, with our findings we conclude that BLE and HCV promote osteogenesis of C3H10T1/2 cells via the GSK-3β/β-catenin pathway and alleviate GIO in rats.

In vitro antioxidant, antibacterial, and antihyperlipidemic potential of ethanolic Avicennia marina leaves extract supported by metabolic profiling

This study aimed to examine the impact of ethanolic Avicennia marina (A. marina) leaves extract against seven pathogenic bacteria and the protective effect of this plant against hyperlipidemia caused by dexamethasone (DEX)-treated rats. Forty-eight male rats weighing between 150 and 200 g were randomly selected into six groups containing eight rats in each group. Moreover, in vitro antioxidant DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging activity, FRAP (ferric reducing antioxidant power), and ABTS assay were also analyzed for leaf extract. Results showed that the IC₅₀ values were observed as 193.9 ± 1.03 μg/mL, 340.29 ± 8.16 μM TE/mg, and 326.8 ± 6.14 μM TE/mg for DPPH, FRAP, and ABTS radical scavenging activities, respectively. A. marina leaves ethanolic extract exhibited higher activity against Candida albicans and Bacillus subtilis, moderate activity against Salmonella typhimurium, and Vibrio damsel. The administration of DEX resulted in significant (P < 0.05) increase in the levels of MDA concentration, TG, TC, LDL, LDH, and glucose but decreased significantly in HDL. Treatment with A. marina extract positively reversed the distorted lipid profile and peroxidation and improved MDA, GSH, NO, and SOD activities in DEX-administered rats. Histological investigation of liver tissue sections showed that the treatment with A. marina leaves extract moderate the fatty change caused by DEX. It is concluded that A. marina leaves extract improved the hypolipidemic property of DEX administration in comparison with standard treatment with atorvastatin.

Bone remodeling stages under physiological conditions and glucocorticoid in excess: Focus on cellular and molecular mechanisms

This review provides a rationale for the cellular and molecular mechanisms of bone remodeling stages under physiological conditions and glucocorticoids (GCs) in excess. Remodeling is a synchronous process involving bone resorption and formation, proceeding through stages of: (1) resting bone, (2) activation, (3) bone resorption, (4) reversal, (5) formation, (6) termination. Bone remodeling is strictly controlled by local and systemic regulatory signaling molecules. This review presents current data on the interaction of osteoclasts, osteoblasts and osteocytes in bone remodeling and defines the role of osteoprogenitor cells located above the resorption area in the form of canopies and populating resorption cavities. The signaling pathways of proliferation, differentiation, viability, and cell death during remodeling are presented. The study of signaling pathways is critical to understanding bone remodeling under normal and pathological conditions. The main signaling pathways that control bone resorption and formation are RANK / RANKL / OPG; M-CSF – c-FMS; canonical and non-canonical signaling pathways Wnt; Notch; MARK; TGFβ / SMAD; ephrinB1/ephrinB2 – EphB4, TNFα – TNFβ, and Bim – Bax/Bak. Cytokines, growth factors, prostaglandins, parathyroid hormone, vitamin D, calcitonin, and estrogens also act as regulators of bone remodeling. The role of non-encoding microRNAs and long RNAs in the process of bone cell differentiation has been established. MicroRNAs affect many target genes, have both a repressive effect on bone formation and activate osteoblast differentiation in different ways. Excess of glucocorticoids negatively affects all stages of bone remodeling, disrupts molecular signaling, induces apoptosis of osteocytes and osteoblasts in different ways, and increases the life cycle of osteoclasts. Glucocorticoids disrupt the reversal stage, which is critical for the subsequent stages of remodeling. Negative effects of GCs on signaling molecules of the canonical Wingless (WNT)/β-catenin pathway and other signaling pathways impair osteoblastogenesis. Under the influence of excess glucocorticoids biosynthesis of biologically active growth factors is reduced, which leads to a decrease in the expression by osteoblasts of molecules that form the osteoid. Glucocorticoids stimulate the expression of mineralization inhibitor proteins, osteoid mineralization is delayed, which is accompanied by increased local matrix demineralization. Although many signaling pathways involved in bone resorption and formation have been discovered and described, the temporal and spatial mechanisms of their sequential turn-on and turn-off in cell proliferation and differentiation require additional research.

Natural medicine delivery from biomedical devices to treat bone disorders: A review

With an increasing life expectancy and aging population, orthopedic defects and bone graft surgeries are increasing in global prevalence. Research to date has advanced the understanding of bone biology and defect repair mechanism, leading to a marked success in the development of synthetic bone substitutes. Yet, the quest for functionalized bone grafts prompted the researchers to find a viable alternative that regulates cellular activity and supports bone regeneration and healing process without causing serious side-effects. Recently, researchers have introduced natural medicinal compounds (NMCs) in bone scaffold that enables them to release at a desirable rate, maintains a sustained release allowing sufficient time for tissue in-growth, and guides bone regeneration process with minimized risk of tissue toxicity. According to World Health Organization (WHO), NMCs are gaining popularity in western countries for the last two decades and are being used by 80% of the population worldwide. Compared to synthetic drugs, NMCs have a broader range of safety window and thus suitable for prolonged localized delivery for bone regeneration. There is limited literature focusing on the integration of bone grafts and natural medicines that provides detailed scientific evidences on NMCs, their toxic limits and particular application in bone tissue engineering, which could guide the researchers to develop functionalized implants for various bone disorders. This review will discuss the emerging trend of NMC delivery from bone grafts, including 3D-printed structures and surface-modified implants, highlighting the significance and potential of NMCs for bone health, guiding future paths toward the development of an ideal bone tissue engineering scaffold. STATEMENT OF SIGNIFICANCE: To date, additive manufacturing technology provids us with many advanced patient specific or defect specific bone constructs exhibiting three-dimensional, well-defined microstructure with interconnected porous networks for defect-repair applications. However, an ideal scaffold should also be able to supply biological signals that actively guide tissue regeneration while simultaneously preventing post-implantation complications. Natural biomolecules are gaining popularity in tissue engineering since they possess a safer, effective approach compared to synthetic drugs. The integration of bone scaffolds and natural biomolecules exploits the advantages of customized, multi-functional bone implants to provide localized delivery of biochemical signals in a controlled manner. This review presents an overview of bone scaffolds as delivery systems for natural biomolecules, which may provide prominent advancement in bone development and improve defect-healing caused by various musculoskeletal disorders.

Curcumin Supplementation Enhances Bone Marrow Mesenchymal Stem Cells to Promote the Anabolism of Articular Chondrocytes and Cartilage Repair

Mesenchymal stem cells derived from bone marrows (BMSCs) and curcumin derived from turmeric were used for osteoarthritis (OA) treatment, respectively. We invested the effects of curcumin supplementation for BMSC therapeutic effects. In vitro, rat BMSCs were identified by dual-immunofluorescent staining of CD44 and CD90, and flow cytometry. Primary articular chondrocytes were identified by toluidine blue staining and immunofluorescent staining of Col2a1. EdU incorporation, migration assay, real-time quantitative polymerase chain reaction, and Western blot analyses were performed to evaluate the alterations of chondrocytes cocultured with BMSCs. In vivo, the rat model of OA was established by monoiodoacetic acid. After intra-articular injection of allogeneic BMSCs, articular cartilage damage and OA progression were evaluated by histological staining, and Osteoarthritis Research Society International and Mankin score evaluation. Although curcumin alone did not improve cell viability of primary articular chondrocytes, it promoted proliferation and migration of chondrocytes when cocultured with BMSCs. Meanwhile, the expression of anabolic genes in chondrocytes was remarkably increased both at mRNA and protein levels. In OA rats, curcumin and BMSCs cooperated to greatly promote articular cartilage repair and retard OA progression. Therefore, curcumin supplementation enhanced the BMSC function for the proliferation and migration of articular chondrocytes, and anabolic gene expression of extracellular matrix in articular chondrocytes in vitro, and the generation of articular cartilage in vivo. Our study shed light on the potential clinical application of curcumin cooperated with BMSCs in cartilage repair for OA treatment.

Emerging Natural-Product-Based Treatments for the Management of Osteoarthritis

Osteoarthritis (OA) is a complex degenerative disease in which joint homeostasis is disrupted, leading to synovial inflammation, cartilage degradation, subchondral bone remodeling, and resulting in pain and joint disability. Yet, the development of new treatment strategies to restore the equilibrium of the osteoarthritic joint remains a challenge. Numerous studies have revealed that dietary components and/or natural products have anti-inflammatory, antioxidant, anti-bone-resorption, and anabolic potential and have received much attention toward the development of new therapeutic strategies for OA treatment. In the present review, we provide an overview of current and emerging natural-product-based research treatments for OA management by drawing attention to experimental, pre-clinical, and clinical models. Herein, we review current and emerging natural-product-based research treatments for OA management.

Curcumin Nanocrystals: Production, Physicochemical Assessment, and In Vitro Evaluation of the Antimicrobial Effects against Bacterial Loading of the Implant Fixture

Background: This study aimed to prepare and study physicochemical properties as well as the antibacterial action of curcumin nanocrystals inside the implant fixture against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Enterococcus faecalis (E. faecalis). Methods: Curcumin nanocrystals were prepared via precipitation combined with the spray drying method. The produced curcumin nanocrystals were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR). Moreover, the in vitro antimicrobial effect of curcumin nanocrystals inside the implant fixture was assessed against E. coli, S. aureus, and E. faecalis. All implant-abutment assemblies were immersed in bacterial suspensions and were incubated at 24, 48, and 72 h. The contents of each implant were cultured to count the colony of bacteria at 37 °C for 24 h. Results: The prepared curcumin nanocrystals with a mean particle size of 95 nm and spherical morphology exhibited a removal rate of 99.99% for all bacteria. In addition, the colony-forming unit (CFU) of bacteria in exposure to nanocrystals significantly was reduced (p < 0.010) by increasing the time. Conclusions: Curcumin nanocrystals can be used inside the implant fixture as an antimicrobial agent in order to more stabilization of the implant.