Atorvastatin, a double weapon in osteoporosis treatment: an experimental and clinical study

The bone-vascular axis: the link between osteoporosis and vascular calcification

Osteoporosis and vascular calcification are chronic metabolic diseases threatening the health of aging people. The incidence of osteoporosis and vascular calcification increases year by year, and has drawn much attention from the scientific and clinical area. Many studies have found that osteoporosis and vascular calcification are not completely independent, but there are close correlations between them in the pathogenesis and underlying mechanisms. The underlying mechanisms of osteoporosis and vascular calcification include aging, oxidative stress, inflammatory response, lipid metabolism, calcium and phosphorus metabolism, vitamins, autophagy, and extracellular vesicles. This review updates the current understanding of the correlation and underlying mechanisms of osteoporosis and vascular calcification, and highlights the complexity of the bone-vascular axis, aiming to provide novel ideas for the prevention and treatment of osteoporosis and vascular calcification.

Effect of local and systemic administration of atorvastatin for improving bone healing on critical defects

This study aimed to evaluate the impact of atorvastatin, administered both locally and systemically, on critical defects in the calvaria of rats. Thirty-six adult rats were randomly assigned to three groups, with all bone defects covered by a collagen membrane. The groups received different treatments: distilled water (GAD), where membranes were soaked in distilled water; systemic application of atorvastatin (GAS) at a dosage of 3.6mg/kg/day through gavage; and local application of atorvastatin (GAL). After 14 and 28 days, all animals were euthanized, and various assessments were conducted, including histometric analysis, measurement of linear residual defect, evaluation of newly formed bone area, determination of membrane and soft tissue area, cell count, and immunohistochemical analysis. Group GAS exhibited a significant reduction in residual defect compared to the other groups (p<0.05) and a lower number of osteocytes (p<0.05) in comparison with other groups. On day 28, both GAL and GAS groups showed a higher number of inflammatory cells compared to GAD (p<0.05). Immunolabeling of CD31 was similar for both groups, but in the case of osteocalcin, there was a significant increase in labeling for groups GAS and GAL between days 14 and 28 postoperative (p<0.05). In conclusion, systemic atorvastatin demonstrated enhanced osteogenesis in critical calvaria defects in rats, suggesting its efficacy in promoting bone regeneration without exerting a notable anti-inflammatory effect.

A coaxial electrospun mat coupled with piezoelectric stimulation and atorvastatin for rapid vascularized bone regeneration

The repair of critical bone defects caused by various clinical conditions needs to be addressed urgently, and the regeneration of large bone defects depends on early vascularization. Therefore, enhanced vascularization of artificial bone grafts may be a promising strategy for the regeneration of critical-sized bone defects. Taking into account the importance of rapid angiogenesis during bone repair and the potential of piezoelectric stimulation in promoting bone regeneration, novel coaxial electrospun mats coupled with piezoelectric materials and angiogenic drugs were fabricated in this study using coaxial electrospinning technology, with a shell layer loaded with atorvastatin (AVT) and a core layer loaded with zinc oxide (ZnO). AVT was used as an angiogenesis inducer, and piezoelectric stimulation generated by the zinc oxide was used as an osteogenesis enhancer. The multifunctional mats were characterized in terms of morphology, core-shell structure, piezoelectric properties, drug release, and mechanical properties, and their osteogenic and angiogenic capabilities were validated in vivo and ex vivo. The results revealed that the coaxial electrospun mats exhibit a porous surface morphology and nanofibers with a core-shell structure, and the piezoelectricity of the mats improved with increasing ZnO content. Excellent biocompatibility, hydrophilicity and cell adhesion were observed in the multifunctional mats. Early and rapid release of AVT in the fibrous shell layer of the mat promoted angiogenesis in human umbilical vascular endothelial cells (HUVECs), whereas ZnO in the fibrous core layer harvested bioenergy and converted it into electrical energy to enhance osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs), and both modalities synergistically promoted osteogenesis and angiogenesis. Furthermore, optimal bone regeneration was achieved in a model of critical bone defects in the rat mandible. This osteogenesis-promoting effect was induced by electrical stimulation via activation of the calcium signaling pathway. This multifunctional mat coupling piezoelectric stimulation and atorvastatin promotes angiogenesis and bone regeneration, and shows great potential in the treatment of large bone defects.

Design, optimization and characterization of atorvastatin loaded chitosan-based polyelectrolyte complex nanoparticles based transdermal patch

AIM

Atorvastatin (ATO) loaded chitosan-based polyelectrolyte complex nanoparticles (PECN) incorporated transdermal patch was developed to enhance its skin permeability and bioavailability.

METHODOLOGY

The ATO loaded PECN were prepared by ionic gelation method and optimized by Box-Behnken design. The optimized batches were evaluated for physicochemical characteristics, in vitro, ex vivo, cell line and stability studies. The optimized ATO-PECN were incorporated into transdermal patches by solvent evaporation method and evaluated for their physicochemical properties, ex vivo skin permeation, in vivo pharmacokinetics and stability study.

RESULTS

The optimized batch of ATO-PECN had average size of 219.2 ± 5.98 nm with 82.68 ± 2.63 % entrapment and 25.41 ± 3.29 mV zeta potential. ATO-PECN showed sustained drug release and higher skin permeation. The cell line study showed that ATO-PECN increased the cell permeability of ATO as compared to ATO suspension. ATO-PECN loaded transdermal patch showed higher skin permeation. The in vivo pharmacokinetic study revealed that the ATO-PECN transdermal patch showed significant (p < 0.05) increase in pharmacokinetic parameters as compared to marketed oral tablet, confirming enhancement in bioavailability of ATO.

CONCLUSIONS

The results of the present work concluded that the ATO-PECN loaded transdermal patch is a promising novel drug delivery system for poorly bioavailable drugs.

Pleotropic effects of statins: the dilemma of wider utilization of statin

BACKGROUND

Apart from reducing the circulating LDL-c and the number of cardiovascular cases as well as fatalities, statins have auxiliary non-lipid-related or cholesterol independent effects, the pleiotropic effects. The aim of the present review is to understand the pleotropic effects of statins.

MAIN BODY

Cardiovascular disease (CVD) is presently the major cause of patient misery as well as mortality among non-communicable diseases (NCDs) in the world. Despite the fact that statins are the most extensively affirmed, prescribed and evidence-based lipid-lowering medicine worldwide that curtail low density lipoprotein cholesterol (LDL-c) levels and the number of cardiovascular cases as well as deaths, statins also elicit auxiliary non-lipid-related or cholesterol independent effects, the pleiotropic effects. Improved endothelial function, significantly lowered oxidative stress, atherosclerotic plaque stabilization, immunomodulatory, cessation of vascular smooth muscle proliferation, effects on bone metabolism, anti-inflammatory, antithrombotic effects, and reduced risk of dementia are among these pleotropic effects. Statins have also been explored for its uses in life threatening diseases like cancer and inflammatory bowel disease. They have been demonstrated to revamp vascular tone. Many research and review articles have been thoroughly studied for this systematic review.

CONCLUSIONS

Statins have not only shown to be benefitial in lowering the levels of LDL-C but have also been established to be advantageous in the treatment of cancer, neurological conditions like dementia, multiple sclerosis, inflammatory bowel disease. Future high-quality trials are needed to include statins in the treatment of these conditions as per guidelines.

Simvastatin reverses the harmful effects of high fat diet on titanium rod osseointegration in ovariectomized rats

INTRODUCTION

The objectives of the present study were to determine whether simvastatin (SIM) could reverse the harmful effects on titanium rod osseointegration in ovariectomized rats fed high-fat diet (HFD).

MATERIALS AND METHODS

Ovariectomized female Sprague-Dawley rats were randomly allocated to three groups and received SIM treatment plus HFD for 12 weeks. We then evaluated the microstructure parameters, histological parameters, biomechanical parameters, bone turnover, and blood lipid level.

RESULTS

After 12 weeks of treatment, SIM can significantly improve bone formation around the titanium rod and osseointegration including higher values of maximum push-out force, bone area ratio (BAR), bone-to-implant contact (BIC), bone mineral density (BMD), bone volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), mean connective density (Conn.D) when compared with the HFD group. In addition, system administration of SIM showed positive effects on collagen type 1 cross-linked C-telopeptide (CTX-1), procollagen I N-terminal propeptide (PINP), total cholesterol (TC), triglycerides (TGL), low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol. Compared with the HFD group, lower values of CTX-1, P1NP, TC, TGL and LDL were observed in the SIM+HFD group (P < 0.05).

CONCLUSION

Our findings revealed that HFD may have an adverse effect on osseointegration in osteoporotic conditions, and the harmful effect of HFD on osseointegration could be reversed by SIM.

Osteoporosis Entwined with Cardiovascular Disease: The Implication of Osteoprotegerin and the Example of Statins

Beyond being epiphenomenon of shared epidemiological factors, the integration of Osteoporosis (OP) with Cardiovascular Disease (CVD) - termed "calcification paradox" - reflects a continuum of aberrant cardiometabolic status. The present review provides background knowledge on "calcification paradox", focusing on the endocrine aspect of vasculature orchestrated by the osteoblastic molecular fingerprint of vascular cells, acquired via imbalance among established modulators of mineralization. Osteoprotegerin (OPG), the well-established osteoprotective cytokine, has recently been shown to exert a vessel-modifying role. Prompted by this notion, the present review interrogates OPG as the potential missing link between OP and CVD. However, so far, the confirmation of this hypothesis is hindered by the equivocal role of OPG in CVD, being both proatherosclerotic and antiatherosclerotic. Further research is needed to illuminate whether OPG could be a biomarker of the "calcification paradox". Moreover, the present review brings into prominence the dual role of statins - cardioprotective and osteoprotective - as a potential illustration of the integration of CVD with OP. Considering that the statins-induced modulation of OPG is central to the statins-driven osteoprotective signalling, statins could be suggested as an illustration of the role of OPG in the bone/vessels crosstalk, if further studies consolidate the contribution of OPG to the cardioprotective role of statins. Another outstanding issue that merits further evaluation is the inconsistency of the osteoprotective role of statins. Further understanding of the varying bone-modifying role of statins, likely attributed to the unique profile of different classes of statins defined by distinct physicochemical characteristics, may yield tangible benefits for treating simultaneously OP and CVD.

Atorvastatin promotes bone formation in aged apoE-/- mice through the Sirt1-Runx2 axis

Background

Statins are the most widely used drugs in elderly patients; the most common clinical application of statins is in aged hyperlipemia patients. There are few studies on the effects and mechanisms of statins on bone in elderly mice with hyperlipemia. The study is to examine the effects of atorvastatin on bone phenotypes and metabolism in aged apolipoprotein E-deficient (apoE^–/–) mice, and the possible mechanisms involved in these changes.

Methods

Twenty-four 60-week-old apoE^–/– mice were randomly allocated to two groups. Twelve mice were orally gavaged with atorvastatin (10 mg/kg body weight/day) for 12 weeks; the others served as the control group. Bone mass and skeletal microarchitecture were determined using micro-CT. Bone metabolism was assessed by serum analyses, qRT-PCR, and Western blot. Bone marrow-derived mesenchymal stem cells (BMSCs) from apoE^–/– mice were differentiated into osteoblasts and treated with atorvastatin and silent information regulator 1 (Sirt1) inhibitor EX-527.

Results

The results showed that long-term administration of atorvastatin increases bone mass and improves bone microarchitecture in trabecular bone but not in cortical bone. Furthermore, the serum bone formation marker osteocalcin (OCN) was ameliorated by atorvastatin, whereas the bone resorption marker tartrate-resistant acid phosphatase 5b (Trap5b) did not appear obviously changes after the treatment of atorvastatin. The mRNA expression of Sirt1, runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and OCN in bone tissue were increased after atorvastatin administration. Western blot showed same trend in Sirt1 and Runx2. The in vitro study showed that when BMSCs from apoE^–/– mice were pretreated with EX527, the higher expression of Runx2, ALP, and OCN activated by atorvastatin decreased significantly or showed no difference compared with the control. The protein expression of Runx2 showed same trend.

Conclusions

Accordingly, the current study validates the hypothesis that atorvastatin can increase bone mass and promote osteogenesis in aged apoE^−/− mice by regulating the Sirt1–Runx2 axis.

Atorvastatin Relieves Cognitive Disorder After Sepsis Through Reverting Inflammatory Cytokines, Oxidative Stress, and Neuronal Apoptosis in Hippocampus

This present research work reports the possible effects and the underlying mechanism of atorvastatin on survival rate and cognitive disorders after sepsis. Sepsis is a life-threatening dysfunction that arises when the body's response to infection causes injury to its own tissues and organs. Diffuse sepsis was induced by cecal ligation and puncture surgery (CLP) in ICR mice. 0.2 mg/kg body weight of atorvastatin was administrated intraperitoneally at 12 h before surgery. The survival of mice was calculated 24 h, 48 h, 72 h, and 96 h after CLP surgery. Two weeks later, open-field test and Morris water maze test were conducted to evaluate the protective effect of atorvastatin. Inflammatory cytokines in plasma, oxidative stress parameters, number of astrocytes, and neuronal cell deaths in the CA3 region of the hippocampus were examined using enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. The results indicate that pretreatment with atorvastatin can increase survival percentage and improve cognitive function. Atorvastatin reversed all these alterations in parallel with a decrease in circulating levels of cytokines (IL-1β, IL-4, IL-6, and TNF-α) in plasma, inhibited the activities of oxidative stress parameters (lower TBARS levels, ratio of GSH/GSSH, and activities of SOD and CAT), enhanced the activity of citrate synthase in brain, and reduced the number of astrocytes and neuronal cell deaths in CA3 region of hippocampus. Overall, our results indicated that atorvastatin exhibited protective effects on survival rate and cognitive disorders after sepsis by inhibiting the release of inflammatory cytokines, oxidative stress, and neuronal apoptosis in brain tissue.

High hydrostatic pressure induces atrial electrical remodeling through upregulation of inflammatory cytokines

AIMS

Hypertension is an independent risk factor for atrial fibrillation (AF). However, the direct effect of hydrostatic pressure on atrial electrical remodeling is unclear. The present study investigated whether hydrostatic pressure is responsible for atrial electrical remodeling and addressed a potential role of inflammation in this pathology.

MAIN METHODS

Whole-cell patch-clamp recordings and biochemical assays were used to study the regulation and expression of ion channels in left atrial appendages in patients with AF, spontaneously hypertensive rats (SHRs), and atrium-derived cells (HL-1 cells) exposed to standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure.

KEY FINDINGS

Both TNF-α and MIF were highly expressed in patients with AF and SHRs. AF inducibility in SHRs was higher after atrial burst pacing, accompanied by a decrease in the L-type calcium current (I_Ca,L), an increase in the transient outward K⁺ current (I_to) and ultra-rapid delayed rectifier K⁺ current (I_Kur), and a shortened action potential duration (APD), which could be inhibited by atorvastatin. Furthermore, exposure to elevated pressure was associated with electrical remodeling of the HL-1 cells. The peak current density of I_Ca,L was reduced, while I_to and I_Kur were increased. Moreover, the expression levels of Kv4.3, Kv1.5, TNF-α, and MIF were upregulated, while the expression of Cav1.2 was downregulated in HL-1 cells after treatment with high hydrostatic pressure (40 mmHg). Atorvastatin alleviated the electrical remodeling and increased inflammatory markers in HL-1 cells induced by high hydrostatic pressure.

SIGNIFICANCE

Elevated hydrostatic pressure led to atrial electrical remodeling and increased AF susceptibility by upregulating inflammation.

Higher concentration of serum C-terminal cross-linking telopeptide of type I collagen is positively related with inflammatory factors in postmenopausal women with H-type hypertension and osteoporosis

OBJECTIVE

To investigate the changes of inflammatory factors and bone metabolism markers in postmenopausal women with H-type hypertension and to assess the relationship between them.

METHODS

Postmenopausal women who were diagnosed with osteoporosis were selected as observation objects. Participants were divided into three groups: only osteoporosis group (osteoporosis group), hypertension combined with osteoporosis group (hypertension group), and H-type hypertension combined with osteoporosis group (H-type hypertension group). The changes in bone mineral density and bone metabolic markers (osteocalcin [OC], procollagen type I N-terminal propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen [CTX]) and inflammatory factors (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]) were compared among three groups.

RESULTS

In the hypertension group and the H-type hypertension group, the bone mineral density of the lumbar spine (0.647 ± 0.038 vs 0.638 ± 0.034 vs 0.668 ± 0.047, P < 0.05) and the femoral neck (0.567 ± 0.047 vs 0.552 ± 0.053 vs 0.618 ± 0.059, P < 0.05) was significantly lower than that in the osteoporosis group. The concentrations of CTX (266.61 ± 64.65 vs 293.09 ± 72.34 vs 235.48 ± 62.85, P < 0.05), IL-6 (44.36 ± 6.45 vs 48.05 ± 8.04 vs 39.06 ± 7.95, P < 0.05) and TNF-α (30.53 ± 6.28 vs 34.52 ± 7.15 vs 28.66 ± 6.19, P < 0.01) in the hypertension group and in the H-type hypertension group were significantly higher than those in the osteoporosis group. The concentrations of OC (30.59 ± 6.43 vs 27.10 ± 6.51, P < 0.05) and PINP (36.36 ± 6.16 vs 33.16 ± 6.77, P < 0.05) in the H-type hypertension group were increased dramatically. The concentration of CTX was positively correlated with the concentration of IL-6 (r = 0.587, P < 0.01) and TNF-α (r = 0.474, P < 0.01) and negatively related with the concentration of OC (r = -0.591, P < 0.01) and PINP (r = -0.646, P < 0.01) and the bone mineral density of the lumbar spine (r = -0.470, P < 0.01) and the femoral neck (r = -0.509, P < 0.01).

CONCLUSION

Higher concentration of serum CTX is found in postmenopausal women with H-type hypertension, which is positively correlated with inflammatory factors. Besides, H-type hypertension could further enhance the activity of osteoclasts and increase the expressions of inflammatory factors, resulting in the aggravation of osteoporosis.

Increased risk of osteoporotic vertebral fracture in rheumatoid arthritis patients with new-onset cardiovascular diseases: a retrospective nationwide cohort study in Taiwan

INTRODUCTION

Both cardiovascular diseases (CVD) and osteoporosis are common comorbidities in rheumatoid arthritis (RA) patients. Although accumulating evidence indicates a link between CVD and osteoporotic fracture, whether CVD contributes to osteoporotic fracture risk in RA has yet to be explored. We examined the incidence rate and risk factors of osteoporotic vertebral fracture in RA patients with new-onset CVD (RA-CVD) and evaluated the effects of medications on such fracture risk.

METHODS

A retrospective study was conducted using a nationwide database from 2000 to 2010: 1267 RA-CVD and 1267 non-CVD patients were enrolled from 30,507 patients with newly diagnosed RA. The main outcome was the development of osteoporotic vertebral fracture. After being adjusted for age, gender, and comorbidities, the Cox proportional hazard model was used to identify independent factors contributing to osteoporotic vertebral fracture.

RESULTS

The adjusted hazard ratio (aHR) of developing osteoporotic vertebral fracture was 1.47-fold greater in RA-CVD group than in non-CVD group (95% confidence interval 1.19-1.81, p < 0.001). Both the age above 40 years and female gender were significant risk factors for developing osteoporotic vertebral fracture in RA-CVD patients. Using patients not taking medication as a reference group, the aHR of osteoporotic vertebral fracture was significantly lower in those receiving statins (0.50), low-dose corticosteroids (0.57), or hydroxychloroquine (0.12).

CONCLUSIONS

The risk of osteoporotic vertebral fracture was significantly increased in RA-CVD patients, particularly women above 40 years of age, and could be reduced by statin therapy. However, the protective effect of low-dose corticosteroids or hydroxychloroquine on osteoporotic vertebral fracture risk needs further validation.

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.

27-Hydroxycholesterol, an endogenous selective estrogen receptor modulator

Estrogen receptors (ERs) mediate the actions of the steroidal estrogens, and are important for the regulation of several physiological and pathophysiological processes, including reproduction, bone physiology, cardiovascular physiology and breast cancer. The unique pharmacology of the ERs allows for certain ligands, such as tamoxifen, to elicit tissue- and context-specific responses, ligands now referred to as selective estrogen receptor modulators (SERMs). Recently, the cholesterol metabolite 27-hydroxychoelsterol (27HC) has been defined as an endogenous SERM, with activities in atherosclerosis, osteoporosis, breast and prostate cancers, and neural degenerative diseases. Since 27HC concentrations closely mirror those of cholesterol, it is possible that 27HC mediates many of the biological effects of cholesterol. This paper provides an overview of ER pharmacology and summarizes the work to date implicating 27HC in various diseases. Wherever possible, we highlight clinical data in support of a role for 27HC in the diseases discussed.