Revisiting estrogen: efficacy and safety for postmenopausal bone health

Formulation and Evaluation of a Self-Microemulsifying Drug Delivery System of Raloxifene with Improved Solubility and Oral Bioavailability

Poor aqueous solubility and dissolution limit the oral bioavailability of Biopharmaceutics Classification System (BCS) class II drugs. In this study, we aimed to improve the aqueous solubility and oral bioavailability of raloxifene hydrochloride (RLX), a BCS class II drug, using a self-microemulsifying drug delivery system (SMEDDS). Based on the solubilities of RLX, Capryol 90, Tween 80/Labrasol ALF, and polyethylene glycol 400 (PEG-400) were selected as the oil, surfactant mixture, and cosurfactant, respectively. Pseudo-ternary phase diagrams were constructed to determine the optimal composition (Capryol 90/Tween 80/Labrasol ALF/PEG-400 in 150/478.1/159.4/212.5 volume ratio) for RLX-SMEDDS with a small droplet size (147.1 nm) and stable microemulsification (PDI: 0.227). Differential scanning calorimetry and powder X-ray diffraction of lyophilized RLX-SMEDDS revealed the loss of crystallinity, suggesting a molecularly dissolved or amorphous state of RLX in the SMEDDS formulation. Moreover, RLX-SMEDDS exhibited significantly higher saturation solubility and dissolution rate in water, simulated gastric fluid (pH 1.2), and simulated intestinal fluid (pH 6.8) than RLX powder. Additionally, oral administration of RLX-SMEDDS to female rats resulted in 1.94- and 1.80-fold higher area under the curve and maximum plasma concentration, respectively, than the RLX dispersion. Collectively, our findings suggest SMEDDS is a promising oral formulation to enhance the therapeutic efficacy of RLX.

Real-world effectiveness of osteoporosis treatments in Germany

This observational study assessed the impact on the fracture incidence of osteoporosis medications in postmenopausal women in Germany. Continued treatment with osteoporosis medications was associated with reductions of fracture rates in a real-world setting.

PURPOSE

The efficacy of osteoporosis medications has been demonstrated in clinical trials, but a lack of evidence exists of their real-world effectiveness. This real-world study assessed the treatment patterns and impact on the fracture incidence of osteoporosis medications in postmenopausal women in Germany.

METHODS

This cohort study used data from the WIG2 benchmark database, a German anonymised healthcare claims database. All women ≥ 50 years of age with ≥ 1 prescription for osteoporosis medication between 1 January 2013 and 31 December 2017 were included. The primary outcome was treatment effectiveness, evaluated as the change in fracture incidence after initiating treatment. Fracture types included all fractures, clinical vertebral, hip and wrist/forearm. Fracture incidence was assessed during the early-treatment period (0-3 months) and the on-treatment period (4-12, 13-24, 25-36 and 37-48 months).

RESULTS

Baseline covariates and treatment patterns were determined for 41,861 patients. The median duration of therapy was longer with denosumab (587 days) than with intravenous ibandronate (451 days), intravenous zoledronate (389 days) or oral bisphosphonates (258 days). The baseline incidence rate of all fractures was higher in patients receiving denosumab than in those receiving other treatments (87.6, 78.2, 56.6 and 66.0 per 1000 person-years for denosumab, oral bisphosphonates, intravenous ibandronate and intravenous zoledronate, respectively). Rates of all fractures declined with continued denosumab (by 38%, 50%, 56% and 67% at 12, 24, 36 and 48 months, respectively) and oral bisphosphonates (by 39%, 44%, 49% and 42%, respectively) treatment.

CONCLUSION

Continued treatment with osteoporosis medications was associated with reductions of fracture rates in a real-world setting.

Severity of Megakaryocyte-Driven Osteosclerosis in Mpig6b-Deficient Mice Is Sex-Linked

Patients with chronic myelofibrosis often suffer from osteosclerosis, which is associated with bone pain and may lead to bone marrow failure. The pathogenesis of myelofibrosis is linked to aberrant megakaryocyte development and function. Null and loss-of-function mutations in MPIG6B, which codes for the inhibitory heparan sulfate receptor G6b-B, result in severe macrothrombocytopenia, large megakaryocyte clusters, and focal primary myelofibrosis in mice and humans. We investigated the development of osteosclerosis in Mpig6b null (Mpig6b^-/- ) mice. Although male and female Mpig6b^-/- mice presented with elevated bone marrow megakaryocyte number and macrothrombocytopenia, female Mpig6b^-/- mice developed progressive splenomegaly starting at 8 weeks of age. Micro-computed tomography (μCT) of femurs showed that female Mpig6b^-/- mice had increased cortical thickness and reduced bone marrow area starting at 8 weeks of age and developed occlusion of the medullary cavity by trabeculae by 16 weeks of age. In contrast, male Mpig6b^-/- mice developed only a small number of trabeculae in the medullary cavity at the proximal diaphysis and demonstrated a temporary decrease in bone volume fraction and trabecular thickness at 16 weeks. Ovariectomy of 10-week-old female Mpig6b^-/- mice prevented the development of medullary cavity osteosclerosis, whereas orchiectomy of male Mpig6b^-/- mice did not exacerbate their disease. Importantly, ovariectomized female Mpig6b^-/- mice also demonstrated improvement in spleen weight compared to sham-operated Mpig6b^-/- mice, establishing estrogen as a contributing factor to the severity of the megakaryocyte-driven osteosclerosis. © 2021 American Society for Bone and Mineral Research (ASBMR).

The Effects of Transdermal Estrogen Delivery on Bone Mineral Density in Postmenopausal Women: A Meta-analysis

Due to its minimal systematic adverse effects, transdermal estrogen is widely used for the prevention of osteoporosis in postmenopausal women. The present meta-analysis aimed to clarify the effects of transdermal estrogen on bone mineral density (BMD) of postmenopausal women. Studies were identified by searching electronic databases including Cochrane Library, MEDLINE, Embase , and CINAHL databases, and also the Sciences Citation Index. Systematic review of articles was published between January 1989 to February 2016.Reference lists of the included articles were also evaluated and consultations were made with relevant experts. While 132 studies included the desired keywords, only nine clinical trials met the inclusion criteria and were finally reviewed. The pooled percent change in BMD was statistically significant in favor of transdermal estrogen. According to resulting pooled estimate, lumbar spine BMD one and two years after transdermal estrogen therapy was respectively 3.4% (95% CI: 1.7-5.1) and 3.7% (95% CI: 1.7-5.7) higher than the baseline values. The test for heterogeneity was not statistically significant based on the I² heterogeneity index. One-two years of transdermal estrogen delivery can effectively increase BMD and protect the bone structure in postmenopausal women.

Flaxseed enhances the beneficial effect of low-dose estrogen therapy at reducing bone turnover and preserving bone microarchitecture in ovariectomized rats

Our previous research showed greatest protection to vertebral bone mineral density and strength in ovariectomized (OVX) rats when lignan- and α-linolenic acid-rich flaxseed (FS) is combined with low-dose estrogen therapy (LD) compared with either treatment alone. This study determined the effects of combined FS+LD on serum and tissue markers of bone turnover and microarchitecture to explain our previous findings. Three-month-old OVX rats were randomized to negative control (NEG), FS, LD or FS+LD for 2 or 12 weeks, meaningful time points for determining effects on markers of bone metabolism and bone structure, respectively. Ground FS was added to the AIN-93M diet (100 g/kg diet) and LD (0.42 μg 17β-estradiol/(kg body weight·day)) was delivered by subcutaneous implant. Sham rats were included as positive control. Bone formation (e.g., osteocalcin), bone resorption (e.g., tartrate-resistant acid phosphatase-5β (TRAP-5β)), as well as osteoprotegerin (OPG) and receptor activator of nuclear factor κ-B ligand (RANKL) were analyzed from the 2-week study by commercial assays (serum) and (or) histology (vertebra). Vertebral bone microarchitecture was measured from the 12-week study using microcomputed tomography. In serum, FS+LD and LD induced lower TRAP-5β and osteocalcin, and higher OPG and OPG/RANKL ratio versus NEG and FS (p < 0.05). In vertebrae, FS+LD induced higher OPG and lower osteocalcin versus NEG (p < 0.01) and did not differ from LD and FS. FS+LD improved bone microarchitecture versus NEG, FS, and LD (p < 0.05). In conclusion, FS+LD protects bone tissue because of a reduction in bone turnover. However, elucidating the distinctive action of FS+LD on bone turnover compared with LD requires further investigation.

The osteoprotective effect of psoralen in ovariectomy-induced osteoporotic rats via stimulating the osteoblastic differentiation from bone mesenchymal stem cells

OBJECTIVE

Psoralea corylifolia extract has been reported to promote bone formation in osteoporotic animals. Psoralen (PSO), a flavonoid glycoside, as the active component of P corylifolia L, is effective in increasing new bone-forming osteoblasts in parietal bone defects. However, the effect and molecular mechanisms of PSO on bone mesenchymal stem cells (bMSCs) in the osteoporotic state are widely unknown. This study was designed to evaluate the osteoprotective effect of PSO in ovariectomy (OVX)-induced rats and to seek possible molecular mechanisms of PSO in bMSCs.

METHODS

We observed the osteogenic effect of PSO (3-month treatment) on osteoporotic rat models induced by OVX via testing bone densitometry, histomorphometries, and immunohistochemistry in vivo. Alkaline phosphatase staining and colony-forming unit-fibroblast and colony-forming unit-adipocyte assays were performed to evaluate the differentiation potential of bMSCs ex vivo. In addition, the molecular targets of PSO in bMSCs were detected by stem cell microarray analysis of 256 genes and confirmed by real-time reverse transcription-polymerase chain reaction.

RESULTS

Micro-CT morphometry analysis showed that PSO significantly improved bone mass indicators including increased trabecular thickness and decreased trabecular space. Meanwhile, PSO elevated the well-known osteogenic marker osteocalcin level in OVX-induced osteoporotic rats. Next, in ex vivo studies, we revealed that PSO facilitated alkaline phosphatase staining and increased the colony-forming unit-fibroblasts. Based on gene expression profile analysis, we screened a set of genes dysregulated in OVX but reversed by PSO treatment. These genes were highly enriched in the Notch signaling pathway, which was documented to play a role in bMSC differentiation.

CONCLUSIONS

Our findings show that PSO promotes bone mass in OVX-induced osteoporotic rats. This effect of PSO is highly related to the stimulation of differentiation of bMSCs to osteoblasts.

Gender differences for initiating teriparatide therapy: baseline data from the Direct Assessment of Nonvertebral Fracture in the Community Experience (DANCE) study

The prospective, observational Direct Assessment of Nonvertebral Fracture in the Community Experience (DANCE) study shows that, among patients with risk factors for osteoporosis, women are more likely to be screened and to receive appropriate treatment than men. There needs to be greater awareness that osteoporosis affects both men and women.

INTRODUCTION

The prospective, observational DANCE study evaluated teriparatide use in the mainland USA and Puerto Rico in patients with osteoporosis in a community setting. This analysis compares baseline characteristics of women and men that may contribute to differences in initiation of teriparatide therapy.

METHODS

Investigators prescribed teriparatide 20 μg/day subcutaneous injection for ≤24 months to 3,698 patients (3,342 women, 356 men) whom they considered appropriate candidates for therapy. Study entry was guided by product labeling. Specific timing and frequency of office visits were not mandated. Treatment decisions were based on the clinical judgment of study investigators and local standards of care.

RESULTS

At baseline, similar proportions of women and men had prior fragility fractures (57% and 59%, respectively) and comorbid conditions that increase fracture risk (83% and 84%, respectively). Women were older than men (mean age 68 vs. 65 year; P < 0.0001) and more likely to have received prior osteoporosis therapy (88% vs. 62%; P < 0.0001). Investigators prescribed teriparatide more often for women than men based on general frailty (21% vs. 16%; P = 0.0151), low body mass index (17% vs. 10%; P = 0.0005), and an inadequate response (58% vs. 36%; P < 0.0001) or intolerance to previous therapy (23% vs. 12%; P < 0.0001). Chronic glucocorticoid therapy was the reason investigators cited most frequently for initiating therapy more often in men than in women (17% vs. 10%; P < 0.0001)

CONCLUSIONS

These results suggest that patients' gender may influence the reasons physicians initiate teriparatide therapy in a community setting.