Distribution of lovastatin to bone and its effect on bone turnover in rats

Statin Therapy and the Risk of Osteoporotic Fractures in Patients with Metabolic Syndrome: a Nested Case-Control Study

OBJECTIVE

We aimed to investigate the association between statin use and the risk of major osteoporotic fractures in patients with metabolic syndrome (MetS).

METHODS

A nested case-control study was performed in patients with MetS (≥50 years) who had no history of osteoporotic fracture using the Korean National Health Insurance Service-Health Screening Cohort. This study included 17,041 patients diagnosed with new-onset osteoporotic fractures and controls matched in a 1:1 ratio by age, sex, body mass index, cohort entry date, and follow-up duration. Conditional logistic regression analysis was used to evaluate covariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

During a 4-year follow-up period, the risk of major osteoporotic fractures was significantly reduced by 9% (OR, 0.91; 95% CI, 0.85-0.97) in statin users compared with that in non-users. Among subtypes of major osteoporotic fracture, a risk reduction with statin therapy was significant for vertebral fracture (OR, 0.86; 95% CI, 0.79-0.94) but not for non-vertebral fracture (OR, 0.97; 95% CI, 0.88-1.06). Longer duration (OR, 0.97; 95% CI, 0.96-0.99, per 1-year increase) and higher cumulative dose (OR, 0.97; 95% CI, 0.95-0.99, per 365 defined daily doses) of statins were negatively associated with the risk of major osteoporotic fracture.

CONCLUSION

This study supports the hypothesis that statin therapy has a beneficial effect on major osteoporotic fractures, especially vertebral fractures, in patients with MetS.

Characterization of chitosan/alginate/lovastatin nanoparticles and investigation of their toxic effects in vitro and in vivo

In this study, chitosan and alginate were selected to prepare alginate/chitosan nanoparticles to load the drug lovastatin by the ionic gelation method. The synthesized nanoparticles loaded with drug were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), laser scattering and differential scanning calorimetry (DSC) methods. The FTIR spectrum of the alginate/chitosan/lovastatin nanoparticles showed that chitosan and alginate interacted with lovastatin through hydrogen bonding and dipolar-dipolar interactions between the C-O, C=O, and OH groups in lovastatin, the C-O, NH, and OH groups in chitosan and the C-O, C=O, and OH groups in alginate. The laser scattering results and SEM images indicated that the alginate/chitosan/lovastatin nanoparticles have a spherical shape with a particle size in the range of 50-80 nm. The DSC diagrams displayed that the melting temperature of the alginate/chitosan/lovastatin nanoparticles was higher than that of chitosan and lower than that of alginate. This result means that the alginate and chitosan interact together, so that the nanoparticles have a larger crystal degree when compared with alginate and chitosan individually. Investigations of the in vitro lovastatin release from the alginate/chitosan/lovastatin nanoparticles under different conditions, including different alginate/chitosan ratios, different solution pH values and different lovastatin contents, were carried out by ultraviolet-visible spectroscopy. The rate of drug release from the nanoparticles is proportional to the increase in the solution pH and inversely proportional to the content of the loaded lovastatin. The drug release process is divided into two stages: a rapid stage over the first 10 hr, then the release becomes gradual and stable. The Korsmeyer-Peppas model is most suitable for the lovastatin release process from the alginate/chitosan/lovastatin nanoparticles in the first stage, and then the drug release complies with other models depending on solution pH in the slow release stage. In addition, the toxicity of alginate/chitosan/lovastatin (abbreviated ACL) nanoparticles was sufficiently low in mice in the acute toxicity test. The LD₅₀ of the drug was higher than 5000 mg/kg, while in the subchronic toxicity test with treatments of 100 mg/kg and 300 mg/kg ACL nanoparticles, there were no abnormal signs, mortality, or toxicity in general to the function or structure of the crucial organs. The results show that the ACL nanoparticles are safe in mice and that these composite nanoparticles might be useful as a new drug carrier.

Impacts of Psychological Stress on Osteoporosis: Clinical Implications and Treatment Interactions

The significant biochemical and physiological effects of psychological stress are beginning to be recognized as exacerbating common diseases, including osteoporosis. This review discusses the current evidence for psychological stress-associated mental health disorders as risk factors for osteoporosis, the mechanisms that may link these conditions, and potential implications for treatment. Traditional, alternative, and adjunctive therapies are discussed. This review is not intended to provide therapeutic recommendations, but, rather, the goal of this review is to delineate potential interactions of psychological stress and osteoporosis and to highlight potential multi-system implications of pharmacological interventions. Review of the current literature identifies several potentially overlapping mechanistic pathways that may be of interest (e.g., glucocorticoid signaling, insulin-like growth factor signaling, serotonin signaling) for further basic and clinical research. Current literature also supports the potential for cross-effects of therapeutics for osteoporosis and mental health disorders. While studies examining a direct link between osteoporosis and chronic psychological stress are limited, the studies reviewed herein suggest that a multi-factorial, personalized approach should be considered for improved patient outcomes in populations experiencing psychological stress, particularly those at high-risk for development of osteoporosis.

Long-term effect of statins on the risk of new-onset osteoporosis: A nationwide population-based cohort study

Background

Several observational cohort and meta-analytical studies in humans have shown that statin users have a lower risk of fractures or greater bone mineral densities (BMD) than nonusers. However, some studies including randomized clinical trials have the opposite results, particularly in Asian populations.

Objective

This study investigates the impacts of statins on new-onset osteoporosis in Taiwan.

Methods

In a nationwide retrospective population-based cohort study, 45,342 subjects aged between 50–90 years having received statin therapy (statin-users) since January 1 2001, and observed through December 31 2013 were selected from the National Health Insurance Research Database of Taiwan. Likewise, 115,594 patients had no statin therapy (statin-non-users) were included as controls in this study. Multivariable Cox proportional hazards analysis for drug exposures was employed to evaluate the association between statin treatment and new-onset of osteoporosis risk. We also used the long-rank test to evaluate the difference of probability of osteoporosis-free survival.

Results

During the 13-year follow-up period, 16,146 of all enrolled subjects (10.03%) developed osteoporosis, including 3097 statin-users (6.83%) and 13,049 statin-non-users (11.29%). Overall, statin therapy reduced the risk of new-onset osteoporosis by 48% (adjusted hazard ratio [HR] 0.52; 95% CI 0.50 to 0.54). A dose-response relationship between statin treatment and the risk of new-onset osteoporosis was observed. The adjusted hazard ratios for new-onset osteoporosis were 0.84 (95% CI, 0.78 to 0.90), 0.56 (95% CI, 0.52 to 0.60) and 0.23 (95% CI, 0.21 to 0.25) when cumulative defined daily doses (cDDDs) ranged from 28 to 90, 91 to 365, and more than 365, respectively, relative to nonusers. Otherwise, high-potency statins (rosuvastatin and atorvastatin) and moderate-potency statin (simvastatin) seemed to have a potential protective effect for osteoporosis.

Conclusions

In this population-based cohort study, we found that statin use is associated with a decreased risk of osteoporosis in both genders. The osteoprotective effect of statins seemed to be more prominent with a dependency on the cumulative dosage and statin intensity.

Comparative impact of systemic delivery of atorvastatin, simvastatin, and lovastatin on bone mineral density of the ovariectomized rats

PURPOSE

In addition to lipid-lowering properties, statins have been suggested to affect bone turnover by increasing the osteoblastic bone formation and blocking the osteoclastogenesis. However, there are many controversial reports regarding the beneficial effect of statins on osteoporosis. In this study, we investigated the therapeutic effects of the most important lipophilic statins administered orally for 60 days to the ovariectomized (OVX) female Sprague-Dawley rats and compared the effects on different harvested trabecular and compact bones.

METHODS

Thirty female rats were divided into five equal groups including the normal rats, untreated OVX rats (negative control), and the OVX rats treated with atorvastatin (20 mg/kg/day), simvastatin (25 mg/kg/day), and lovastatin (20 mg/kg/day). The osteoporotic animals were treated daily for 60 days and euthanized at the end of experiments. The effectiveness of these treatments was evaluated by biomechanical testing, histopathologic, histomorphometric, micro-CT scan, real-time PCR, and serum biochemical analysis. Moreover, the hepatotoxicity and rhabdomyolysis related with these treatments were assessed by biochemistry analysis and histopathological evaluation.

RESULTS

The results and statistical analysis showed that systemic delivery of simvastatin and lovastatin significantly increased serum calcium level, expression of osteogenic genes, bone mineral density (BMD), and biomechanical properties in comparison to the untreated OVX rats, especially in trabecular bones (P < 0.05). The results of different analysis also indicated that there was no statistical difference between the atorvastatin-treated animals and the negative control. Among all treatments, only atorvastatin showed an evident hepatotoxicity and myopathy.

CONCLUSIONS

It was concluded that the lovastatin and simvastatin efficiently ameliorated the OVX-induced osteoporosis. Moreover, the simvastatin-treated animals showed more resemblance to the normal group in terms of BMD, expression of osteogenic genes, serum biochemical parameters, histomorphometric findings, and biomechanical performance with no significant side-effects.

The Effects of Tocotrienol and Lovastatin Co-Supplementation on Bone Dynamic Histomorphometry and Bone Morphogenetic Protein-2 Expression in Rats with Estrogen Deficiency

Both tocotrienol and statins are suppressors of the mevalonate pathway. Supplementation of tocotrienol among statin users could potentially protect them against osteoporosis. This study aimed to compare the effects of tocotrienol and lovastatin co-supplementation with individual treatments on bone dynamic histomorphometric indices and bone morphogenetic protein-2 (BMP-2) gene expression in ovariectomized rats. Forty-eight female Sprague-Dawley rats were randomized equally into six groups. The baseline was sacrificed upon receipt. All other groups were ovariectomized, except for the sham group. The ovariectomized groups were administered orally daily with (1) lovastatin 11 mg/kg/day alone; (2) tocotrienol derived from annatto bean (annatto tocotrienol) 60 mg/kg/day alone; (3) lovastatin 11 mg/kg/day, and annatto tocotrienol 60 mg/kg/day. The sham and ovariectomized control groups were treated with equal volume of vehicle. After eight weeks of treatment, the rats were sacrificed. Their bones were harvested for bone dynamic histomorphometry and BMP-2 gene expression. Rats supplemented with annatto tocotrienol and lovastatin concurrently demonstrated significantly lower single-labeled surface, but increased double-labeled surface, mineralizing surface, mineral apposition rate and bone formation rate compared to individual treatments (p < 0.05). There was a parallel increase in BMP-2 gene expression in the rats receiving combined treatment (p < 0.05). The combination of annatto tocotrienol and lovastatin exerted either additively or synergistically on selected bone parameters. In conclusion, tocotrienol can augment the bone formation and mineralization in rats receiving low-dose statins. Supplementation of tocotrienol in statin users can potentially protect them from osteoporosis.

γ-Tocotrienol protects against ovariectomy-induced bone loss via mevalonate pathway as HMG-CoA reductase inhibitor

γ-Tocotrienol (GT3), an analogue of vitamin E, has gained increasing scientific interest recently as it provides significant health benefits. GT3 exerts its biological effects not only by virtue of antioxidant properties but also by inhibiting hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase. Studies have reported that the mevalonate pathway is relevant for bone metabolism and HMG-CoA reductase inhibitors can increase bone mass and are useful in osteoporosis therapy. However, whether it is involved in the bone anabolic activity of GT3 is not clear. This study was conducted to investigate the ability of GT3 to protect against ovariectomy-induced bone loss, as well as the correlation between the protections and mevalonate pathway. Results showed that mice supplemented with 100mg/kg emulsified GT3 via subcutaneous injection once per month for three months were significantly protected from ovariectomy-induced bone loss as evaluated by various bone structural parameters, bone metabolic gene expression levels and serum levels of biochemical markers for bone resorption and bone formation. Importantly, the effect of GT3 on preventing against ovariectomy-induced bone loss could be reversed by daily supplementation with mevalonate, indicating that GT3 may via an HMG-CoA reductase-dependent mechanism to protect against ovariectomy-induced bone loss. Our results suggest that GT3 is suitable as dietary supplement and has potential as an alternative drug to treat or prevent osteoporosis.

Relationship between bone turnover biomarkers, mandibular bone mineral density, and systemic skeletal bone mineral density in premenopausal and postmenopausal Indian women

OBJECTIVE

Postmenopausal osteoporosis is one of the most common metabolic bone disorders. Osteoporosis is reported to cause bone loss in the alveolar processes of maxilla and mandible, which provide bony framework for tooth anchorage. However, the association between systemic osteoporosis and oral health remains controversial. Available evidence suggests that Indian women have lower peak bone mass than their Western/other Asian counterparts. The present study evaluated the relationship between mandibular bone mineral density (mBMD), systemic skeletal BMD, and bone metabolism in premenopausal and postmenopausal Indian women.

METHODS

One hundred twenty-four premenopausal and 247 postmenopausal healthy women were included in the study. The BMD of the body of mandible, radius ultradistal, total hip, femur neck, and lateral spine were measured using dual-energy x-ray absorptiometry. Serum and urine biomarkers were determined using commercial kits.

RESULTS

Univariate regression analysis followed by stepwise multivariate regression analysis to obtain the best fit model demonstrated the BMD of radius ultradistal, serum inorganic phosphorus, estradiol, and sex hormone-binding globulin as significant predictors of mBMD in premenopausal women. The BMD of femur neck, serum ionized calcium, bone-specific alkaline phosphatase, osteocalcin, and urine total pyridinoline were significantly associated with mBMD in postmenopausal women. The significant association between mBMD and number of teeth present was observed in the whole group of premenopausal and postmenopausal women.

CONCLUSIONS

Varied predictors of mBMD were observed in premenopausal and postmenopausal women. The results suggest that the screening for these biomarkers and serum ionized calcium should be useful (1) to assess the status of mBMD particularly in women requiring surgical dental intervention that include bone manipulation and (2) for early detection and management of women with the risk of developing osteoporosis.

Statins and the joint: multiple targets for a global protection?

OBJECTIVES

Evidence exists that the pleiotropic properties of the hydroxy-methyl-glutaryl Coenzyme A reductase inhibitors (statins) are not restricted to the cardiovascular system, as they can also favorably affect the joints, with intriguing implications for the treatment of many rheumatic diseases. In the view of the increasing interest on this topic, we here review the current state of the art.

METHODS

The PubMed database was searched for articles published between 1966 and 2010 for key words referring to statins and joint diseases. All relevant English-written articles were reviewed.

RESULTS

Many pivotal studies clearly demonstrated that HMG-CoA reductase inhibitors exert a wide spectrum of beneficial effects on the 3 main compartments of the joint, ie, the synovium, the cartilage, and the subchondral bone. Such (1) anti-inflammatory, (2) immunomodulating, and (3) anabolic effects strongly support a potential role of these drugs in the treatment and/or the prevention of the most important chronic joint diseases. However, although the majority of the in vivo studies with statins on animal models of inflammatory and degenerative joint diseases showed a marked protective activity substantially confirming the in vitro experiments, data arising from clinical trials are less probative and more conflicting.

CONCLUSIONS

Statins display multiple joint-protective effects. Since oral administration of statins could result in a relatively low drug bioavailability to the joints, alternative routes of administration of the drug (transdermal, intra-articular) and/or specific delivery systems should be developed to establish the entire therapeutic potential of statins in this clinical setting.

Local low-dose lovastatin delivery improves the bone-healing defect caused by Nf1 loss of function in osteoblasts

Postfracture tibial nonunion (pseudoarthrosis) leads to lifelong disability in patients with neurofibromatosis type I (NF1), a disorder caused by mutations in the NF1 gene. To determine the contribution of NF1 in bone healing, we assessed bone healing in the Nf1(ob) (-/-) conditional mouse model lacking Nf1 specifically in osteoblasts. A closed distal tibia fracture protocol and a longitudinal study design were used. During the 21- to 28-day postfracture period, callus volume, as expected, decreased in wild-type but not in Nf1(ob) (-/-) mice, suggesting delayed healing. At these two time points, bone volume (BV/TV) and volumetric bone mineral density (vBMD) measured by 3D micro-computed tomography were decreased in Nf1(ob) (-/-) callus-bridging cortices and trabecular compartments compared with wild-type controls. Histomorphometric analyses revealed the presence of cartilaginous remnants, a high amount of osteoid, and increased osteoclast surfaces in Nf1(ob) (-/-) calluses 21 days after fracture, which was accompanied by increased expression of osteopontin, Rankl, and Tgfbeta. Callus strength measured by three-point bending 28 days after fracture was reduced in Nf1(ob) (-/-) versus wild-type calluses. Importantly, from a clinical point of view, this defect of callus maturation and strength could be ameliorated by local delivery of low-dose lovastatin microparticles, which successfully decreased osteoid volume and cartilaginous remnant number and increased callus BV/TV and strength in mutant mice. These results thus indicate that the dysfunctions caused by loss of Nf1 in osteoblasts impair callus maturation and weaken callus mechanical properties and suggest that local delivery of low-dose lovastatin may improve bone healing in NF1 patients.