Role of Bisphosphonates in Postmenopausal Women with Osteoporosis to Prevent Future Fractures: A Literature Review

Understanding Physicians’ Perceptions of Patient-Identified Barriers to Osteoporosis Medication Initiation: A Cognitive Mapping Approach

Objective

Interventions to initiate medication and increase adherence for postmenopausal women who have had a fragility fracture were not always successful. The purpose of this study was to derive an empirical framework for patient-identified barriers to osteoporosis medication initiation and adherence from physician experts.

Methods

A cognitive mapping approach involving nominal group technique (NGT) meetings and a card sorting and rating task were used to obtain formative data. We first conducted four NGT meetings with 18 women patients who were not on osteoporosis treatment to identify barriers to osteoporosis medication, then invited 27 osteoporosis physicians to sort and rate 25 patients identified barriers. Descriptive analysis, multidimensional scaling analysis, and hierarchical cluster analysis were applied for data analysis.

Results

A two-dimensional five-cluster cognitive map was derived to provide an organizational framework for understanding patients perceived barriers to medication initiation and adherence. The five clusters were concerns about side effects, experience of side effects, lifestyle changes, medication access and complexity, and patient uncertainty about treatment and trust in the provider. The two dimensions were interpreted as internal to patients (X-axis) and external to patients (Y-axis).

Conclusions/Implications

Views of patients solicited in a structured format provided directions to help in designing interventions to improve osteoporosis medication initiation and adherence.

Effects of Drynaria Total Flavonoid on the Microstructure of the Mandible in Ovariectomized Rats

Background

The aim of this study is to investigate the effects of Drynaria total flavonoids (DTF) on mandible microarchitecture, serum estrogen (E2), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) levels in an ovariectomy-induced osteoporosis rat model.

Material/Methods

Thirty female Sprague-Dawley rats were divided into 5 groups (n=6 per group): sham surgery, ovariectomy (OVX), and low-dose, middle-dose, and high-dose DTF. Mandibular osteoporosis was induced by ovariectomy; an equal amount of ovary-sized fat tissue was removed from the sham group. The DTF-treated groups were given DTF gavage at different doses for 12 weeks; the sham and OVX groups were given saline. After the treatment phase, the effects of DTF on the microarchitecture of the mandible were evaluated by measuring bone density, maximum load, morphometric parameters, and histopathological alterations. Serum E2, OPG, and RANKL levels were measured.

Results

The OVX group showed obvious osteoporosis in the mandible and decreased serum E2 levels and OPG/RANKL ratio. The low-dose group did not show significant improvement in mandibular microstructure. The middle-dose group showed significantly ameliorated osteoporosis. The high-dose group had further improvement in bone microstructures and increase of OPG/RANKL over the middle-dose group. Furthermore, ovariectomy significantly decreased serum E2, but DTF treatment failed to restore serum E2 levels.

Conclusions

Ovariectomy can cause significant bone loss in the rat mandible and a decrease in serum E2 and OPG/RANKL. DTF significantly improved the mandibular microstructure and restored OPG/RANKL balance, but it did not restore the decreased serum E2 concentration following ovariectomy.

MicroRNA-505 is involved in the regulation of osteogenic differentiation of MC3T3-E1 cells partially by targeting RUNX2

Objective

Evidence suggests that microRNAs (miRNAs) regulate the expression of genes involved in bone metabolism. This study aimed to investigate the role of miR-505 in the osteogenic differentiation of MC3T3-E1 cells.

Methods

We performed miRNA sequencing to identify differentially expressed miRNAs between MC3T3-E1 cells treated with osteogenic induction medium (OIM) and control cells. Bioinformatics analysis was performed by using the TargetScan and miRDB databases. The expression of miR-505 in MC3T3-E1 cells was detected during osteogenic differentiation. After transfection with miR-505 mimic or miR-505 inhibitor, MC3T3-E1 cells were induced to differentiate into osteoblasts, and the expression of osteogenic differentiation markers (Runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), and osterix (OSX)) was detected.

Results

miR-505 was the most downregulated miRNA among the differentially expressed miRNAs. The RUNX2 gene was identified as a potential target of miR-505 using the target prediction program. miR-505 expression was downregulated during osteogenic differentiation of MC3T3-E1 cells. The expression of osteogenic marker genes was inhibited in MC3T3-E1 cells after transfection with miR-505. However, the expression of osteogenic marker genes was upregulated after transfection with miR-505 inhibitor.

Conclusion

This study is the first to report miR-505 could bind to the RUNX2 gene and thus regulate partly the dysfunction of osteoblasts differentiation, which is expected to be targets for the treatment of osteoporosis.