Hesperetin alleviated glucocorticoid-induced inhibition of osteogenic differentiation of BMSCs through regulating the ERK signaling pathway

Advances in the Pathogenesis of Steroid-Associated Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic condition characterized by bone cell ischemia, necrosis, bone trabecular fracture, and clinical symptoms such as pain, femoral head collapse, and joint dysfunction that can lead to disability. The disability rate of ONFH is very high, which imposes a significant economic burden on both families and society. Steroid-associated osteonecrosis of the femoral head (SANFH) is the most common type of ONFH. However, the pathogenesis of SANFH remains unclear, and it is an urgent challenge for orthopedic surgeons to explore it. In this paper, the pathogenesis of SANFH and its related signaling pathways were briefly reviewed to enhance comprehension of the pathogenesis and prevention of SANFH.

Formulation of a Novel Hesperetin-Loaded Nanoemulsion and Its Promising Effect on Osteogenesis

Alternative therapies associating natural products and nanobiotechnology show new perspectives on controlled drug release. In this context, nanoemulsions (NEs) present promising results for their structural design and properties. Hesperetin (HT), a flavonoid mainly found in citrus fruits, presents highlighted bone benefits. In this context, we developed a hesperetin-loaded nanoemulsion (HT-NE) by sonication method and characterized it by dynamic light scattering, analyzing its encapsulation efficiency, and cumulative release. The biocompatibility in human osteoblasts Saos-2-like was evaluated by the cytotoxicity assay and IC50. Then, the effects of the HT-NE on osteogenesis were evaluated by the cellular proliferation, calcium nodule formation, bone regulators gene expression, collagen quantification, and alkaline phosphatase activity. The results showed that the formulation presented ideal values of droplet size, polydispersity index, and zeta potential, and the encapsulation efficiency was 74.07 ± 5.33%, showing a gradual and controlled release. Finally, HT-NE was shown to be biocompatible and increased cellular proliferation, and calcium nodule formation, regulated the expression of Runx2, ALPL, and TGF-β genes, and increased the collagen formation and alkaline phosphatase activity. Therefore, the formulation of this NE encapsulated the HT appropriately, allowing the increasing of its effects on mechanisms to improve or accelerate the osteogenesis process.

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.

Osteoprotective effects of flavonoids: Evidence from in vivo and in vitro studies (Review)

Osteoporosis is a systemic bone disease characterized by decreased bone mass and quality and bone micro‑architecture degradation. Its primary cause is disorder of bone metabolism: Over‑formation of osteoclasts, resulting in increased bone resorption and insufficient osteogenesis. Traditional herbal flavonoids can be used as alternative drugs to prevent and treat osteoporosis due to their wide range of sources, structural diversity and less adverse effects. The present paper reviewed six flavonoids, including quercetin, icariin, hesperitin, naringin, chrysin and pueraria, that promote bone formation and have been widely studied in the literature over the past five years, with the aim of providing novel ideas for the development of drugs for bone‑associated disease.

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.

Therapeutic effect of platelet-rich plasma on glucocorticoid-induced rat bone marrow mesenchymal stem cells in vitro

BACKGROUND

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is a progressive and disabling disease caused by long-term or high-dose glucocorticoid use. Decreased osteogenesis and proliferation of bone marrow mesenchymal stem cells (BMSCs) are the main pathogenesis of GIONFH. Platelet-rich plasma (PRP) has been shown to play a promising role in bone regeneration. However, the effects of PRP on glucocorticoid-induced BMSCs inhibition remains elusive. The objective of this study was to explore whether PRP could improve the in vitro biological activities of BMSCs inhibited by high-dose glucocorticoid in vitro.

METHODS

In this study, a dexamethasone (Dex)-induced in vitro cell model was established. The effects of PRP on proliferation, migration, cell cycle and apoptosis of rat BMSCs induced with high-dose Dex compared to BMSC_CTRL, using CCK-8 assay, transwell, flow cytometry and TUNEL assay, respectively. We further performed the alkaline phosphatase (ALP) and alizarin red (ALR) staining to explore the influence of PRP on osteogenic differentiation. Western Blot was used to detect the expression of Bcl-2, Caspase-3, RUNX2 apoptosis, and osteogenic-related proteins.

RESULTS

We observed increased apoptosis rate and Caspase-3 expression, and the decreased migration and osteogenic differentiation, and down-regulation of RUNX-2 and Bcl-2 expression in Dex-induced BMSCs. PRP could reverse these inhibitory effects of Dex, and enhance the BMSCs proliferation, migration, and osteogenic ability in vitro.

CONCLUSION

Our vitro study showed that PRP significantly protected BMSCs from Dex-induced apoptosis, and further promoted BMSCs proliferation, migration, and osteogenic differentiation. This study provides a scientific basis for the prevention and treatment of GIONFH with PRP. Meanwhile, it also lays the foundation for the application of PRP in other musculoskeletal diseases.