Total glycosides from Eucommia ulmoides seed promoted osteogenic differentiation of adipose-derived mesenchymal stem cells and bone formation in ovariectomized rats through regulating Notch signaling pathway

Regulation of bone homeostasis by traditional Chinese medicine active scaffolds and enhancement for the osteoporosis bone regeneration

ETHNOPHARMACOLOGICAL RELEVANCE

The active ingredients of traditional Chinese medicine (TCM), such as naringin (NG), Eucommiol, isopsoralen, icariin, Astragalus polysaccharides, and chondroitin sulfate, contained in Drynariae Rhizoma, Eucommiae Cortex, Psoralea corylifolia, Herba Epimedii, Astragalus radix and deer antler, are considered promising candidates for enhancing the healing of osteoporotic defects due to their outstanding bone homeostasis regulating properties. They are commonly used to activate bone repair scaffolds.

AIM OF THE REVIEW

Bone repair scaffolds are inadequate to meet the demands of osteoporotic defect healing due to the lack of regulation of bone homeostasis. Therefore, selecting bone scaffolds activated with TCM to improve the therapeutic effect of repairing osteoporotic bone defects.

MATERIALS AND METHODS

To gather information on bone scaffold activated by traditional Chinese medicine, we conducted a thorough search of several scientific databases, including Google Scholar, Web of Science, Scifinder, Baidu Scholar, PubMed, and China National Knowledge Infrastructure (CNKI).

RESULTS

This review discusses the mechanism of TCM active ingredients in regulating bone homeostasis, including stimulating bone formation and inhibiting bone resorption process and the healing mechanism of traditional bone repair scaffolds activated by them for osteoporotic defect healing.

CONCLUSION

In general, the introduction of TCM active ingredients provides a novel therapeutic approach for modulating bone homeostasis and facilitating osteoporotic defect healing, and also offers a new strategy for design of other unconventional bone defect healing materials.

Intake of dietary flavonoids in relation to bone loss among U.S. adults: a promising strategy for improving bone health

Dietary flavonoids have been recommended for improving bone health due to their antioxidant, anti-inflammatory and osteogenic properties. However, the effectiveness of each flavonoid subclass in the prevention and treatment of osteoporosis remains controversial. The objective of the current study was to examine the association between the intake of flavonoid subclasses and bone loss in 10 480 U.S. adults in the National Health and Nutrition Examination Survey. We employed a multinomial logistic regression model to calculate the odds ratios (OR) and 95% confidence intervals (95% CI). The intake of flavones, isoflavones, and flavanones was beneficially associated with osteoporosis (ORQ5 vs. Q1 = 0.44; 95% CI: 0.30-0.64 for flavones; ORQ5 vs. Q1 = 0.53; 95% CI: 0.37-0.77 for isoflavones; ORQ5 vs. Q1 = 0.66; 95% CI: 0.45-0.97 for flavanones). A higher intake of flavones and flavanones was significantly associated with a lower risk of bone loss at the femoral neck rather than the lumbar spine. Notably, stratified analysis showed that genistein had a harmful association with osteopenia in the population with lower serum calcium levels, whereas it had a beneficial association with osteoporosis in the population with higher serum calcium levels. Multiple sensitivity analyses were performed to test the robustness of the results, including subgroup analysis, exclusion of individuals' use of anti-osteoporosis, corticosteroid, and estrogenic medications, adjusting more potential confounders and calculation of the E-value. Overall, incorporating this modifiable diet into an individual's lifestyle could provide potential possibilities to prevent and ameliorate osteoporosis.

Therapeutic Potential of Chlorhexidine-Loaded Calcium Hydroxide-Based Intracanal Medications in Endo-Periodontal Lesions: An Ex Vivo and In Vitro Study

Endo-periodontal lesions are challenging clinical situations where both the supporting tissues and the root canal of the same tooth are infected. In the present study, chlorhexidine (CHX)-loaded calcium hydroxide (CH) pastes were used as intracanal medications (ICMs). They were prepared and tested on pathogens found in both the root canal and the periodontal pocket. Exposure to 0.5% and 1% CHX-loaded ICMs decreased the growth of Porphyromonas gingivalis and was effective in eradicating or inhibiting an Enterococcus faecalis biofilm. CH was injected into the root canal of extracted human teeth immersed in deionized water. CHX-loaded ICMs resulted in the transradicular diffusion of active components outside the tooth through the apex and the lateral dentinal tubules, as shown by the release of CHX (from 3.99 µg/mL to 51.28 µg/mL) and changes in pH (from 6.63 to 8.18) and calcium concentrations (from 2.42 ppm to 14.67 ppm) after 7 days. The 0.5% CHX-loaded ICM was non-toxic and reduced the release of IL-6 by periodontal cells stimulated by P. gingivalis lipopolysaccharides. Results indicate that the root canal may serve as a reservoir for periodontal drug delivery and that CHX-based ICMs can be an adjuvant for the control of infections and inflammation in endo-periodontal lesions.

Recent Advancements in Electrospun Chitin and Chitosan Nanofibers for Bone Tissue Engineering Applications

Treatment of large segmental bone loss caused by fractures, osteomyelitis, and non-union results in expenses of around USD 300,000 per case. Moreover, the worst-case scenario results in amputation in 10% to 14.5% of cases. Biomaterials, cells, and regulatory elements are employed in bone tissue engineering (BTE) to create biosynthetic bone grafts with effective functionalization that can aid in the restoration of such fractured bones, preventing amputation and alleviating expenses. Chitin (CT) and chitosan (CS) are two of the most prevalent natural biopolymers utilized in the fields of biomaterials and BTE. To offer the structural and biochemical cues for augmenting bone formation, CT and CS can be employed alone or in combination with other biomaterials in the form of nanofibers (NFs). When compared with several fabrication methods available to produce scaffolds, electrospinning is regarded as superior since it enables the development of nanostructured scaffolds utilizing biopolymers. Electrospun nanofibers (ENFs) offer unique characteristics, including morphological resemblance to the extracellular matrix, high surface-area-to-volume ratio, permeability, porosity, and stability. This review elaborates on the recent strategies employed utilizing CT and CS ENFs and their biocomposites in BTE. We also summarize their implementation in supporting and delivering an osteogenic response to treat critical bone defects and their perspectives on rejuvenation. The CT- and CS-based ENF composite biomaterials show promise as potential constructions for bone tissue creation.

Geniposide ameliorated dexamethasone-induced endoplasmic reticulum stress and mitochondrial apoptosis in osteoblasts

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommia ulmoides Oliver has been traditionally used for treatment of various diseases, including osteoporosis, knee pain, and paralysis. The extract of Eucommia ulmoides has been reported to stimulate the bone formation and suppress the bone resorption, leading to protection against osteoporosis (OP). Geniposide (GEN) has been considered as one of the effective compounds responsible for the therapeutic efficacy of Eucommia ulmoides against OP.

AIM OF THE STUDY

To explore whether GEN protected against dexamethasone (DEX)-induced osteoporosis (OP) by activating NRF2 expression and inhibiting endoplasmic reticulum (ER) stress.

MATERIALS AND METHODS

The DEX-induced rat OP models were duplicated. The pathological changes were examined by histological/immunohistochemical evaluation and micro-computed tomography (micro-CT) assessment. Apoptosis was detected by a flow cytometer. Mitochondrial Ca²⁺ concentrations and mitochondrial membrane potential were detected. Western blot assays were used to detect the protein expression.

RESULTS

GEN effectively reversed DEX-induced pathological changes of trabecular bone in rats. In addition, the DEX-increased expression of ATF4/CHOP was also ameliorated. In MC3T3-E1 cells, DEX promoted endoplasmic reticulum (ER) stress and mitochondrial apoptosis. Inhibition of ER stress abolished the induction of apoptosis by DEX. Similarly, GEN significantly ameliorated DEX-induced mitochondrial apoptosis. The possible underlying mechanism might be associated with the pharmacological effects of GEN on activating the expression of NRF2 and alleviating ER stress in DEX-treated MC3T3-E1 cells.

CONCLUSION

GEN ameliorated DEX-induced ER stress and mitochondrial apoptosis in osteoblasts.

Network pharmacology of iridoid glycosides from Eucommia ulmoides Oliver against osteoporosis

Eucommia ulmoides Oliver is one of the commonly used traditional Chinese medicines for the treatment of osteoporosis, and iridoid glycosides are considered to be its active ingredients against osteoporosis. This study aims to clarify the chemical components and molecular mechanism of iridoid glycosides of Eucommia ulmoides Oliver in the treatment of osteoporosis by integrating network pharmacology and molecular simulations. The active iridoid glycosides and their potential targets were retrieved from text mining as well as Swiss Target Prediction, TargetNet database, and STITCH databases. At the same time, DisGeNET, GeneCards, and Therapeutic Target Database were used to search for the targets associated with osteoporosis. A protein–protein interaction network was built to analyze the interactions between targets. Then, DAVID bioinformatics resources and R 3.6.3 project were used to carry out Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis. Moreover, interactions between active compounds and potential targets were investigated through molecular docking, molecular dynamic simulation, and binding free energy analysis. The results showed that a total of 12 iridoid glycosides were identified as the active iridoid glycosides of Eucommia ulmoides Oliver in the treatment of osteoporosis. Among them, aucubin, reptoside, geniposide and ajugoside were the core compounds. The enrichment analysis suggested iridoid glycosides of Eucommia ulmoides Oliver prevented osteoporosis mainly through PI3K-Akt signaling pathway, MAPK signaling pathway and Estrogen signaling pathway. Molecular docking results indicated that the 12 iridoid glycosides had good binding ability with 25 hub target proteins, which played a critical role in the treatment of osteoporosis. Molecular dynamic and molecular mechanics Poisson–Boltzmann surface area results revealed these compounds showed stable binding to the active sites of the target proteins during the simulations. In conclusion, our research demonstrated that iridoid glycosides of Eucommia ulmoides Oliver in the treatment of osteoporosis involved a multi-component, multi-target and multi-pathway mechanism, which provided new suggestions and theoretical support for treating osteoporosis.

The Role of Flavonoids in the Osteogenic Differentiation of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) play an important role in developing bone tissue engineered constructs due to their osteogenic and chondrogenic differentiation potential. MSC-based tissue engineered constructs are generally considered a safe procedure, however, the long-term results obtained up to now are far from satisfactory. The main causes of these therapeutic limitations are inefficient homing, engraftment, and directional differentiation. Flavonoids are a secondary metabolite, widely existed in nature and have many biological activities. For a long time, researchers have confirmed the anti-osteoporosis effect of flavonoids through in vitro cell experiments, animal studies. In recent years the regulatory effects of flavonoids on mesenchymal stem cells (MSCs) differentiation have been received increasingly attention. Recent studies revealed flavonoids possess the ability to modulate self-renewal and differentiation potential of MSCs. In order to facilitate further research on MSCs osteogenic differentiation of flavonoids, we surveyed the literature published on the use of flavonoids in osteogenic differentiation of MSCs, and summarized their pharmacological activities as well as the underlying mechanisms, aimed to explore their promising therapeutic application in bone disorders and bone tissue engineered constructs.