Vascular action of bisphosphonates: In vitro effect of alendronate on the regulation of cellular events involved in vessel pathogenesis

Non-nitrogen-containing bisphosphonates and nitrogen-containing bisphosphonates for the treatment of atherosclerosis and vascular calcification: A meta-analysis

BACKGROUND

The role of non-nitrogen-containing bisphosphonates (non-N-BPs) and nitrogen-containing bisphosphonates (N-BPs) in the treatment of atherosclerosis (AS) and vascular calcification (VC) is uncertain. This meta-analysis was conducted to evaluate the efficacy of non-N-BPs and N-BPs in the treatment of AS and VC.

METHODS

The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases were searched from their inception to July 5th, 2023. Eligible studies comparing bisphosphonates (BPs) versus no BPs in the treatment of AS and VC were included. The data were analyzed using Review Manager Version 5.3.

RESULTS

Seventeen studies were included in this meta-analysis. Twelve were randomized control trials (RCTs), and 5 were nonrandomized studies. Overall, 813 patients were included in the BPs group, and 821 patients were included in the no BPs group. Compared with no BP treatment, non-N-BP or N-BP treatment did not affect serum calcium (P > .05), phosphorus (P > .05) or parathyroid hormone (PTH) levels (P > .05). Regarding the effect on serum lipids, non-N-BPs decreased the serum total cholesterol (TC) level (P < .05) and increased the serum triglyceride (TG) level (P < .01) but did not affect the serum low-density lipoprotein cholesterol (LDL-C) level (P > .05). N-BPs did not affect serum TC (P > .05), TG (P > .05) or LDL-C levels (P > .05). Regarding the effect on AS, non-N-BPs did not have a beneficial effect (P > .05). N-BPs had a beneficial effect on AS, including reducing the intima-media thickness (IMT) (P < .05) and plaque area (P < .01). For the effect on VC, non-N-BPs had a beneficial effect (P < .01), but N-BPs did not have a beneficial effect (P > .05).

CONCLUSION

Non-N-BPs and N-BPs did not affect serum calcium, phosphorus or PTH levels. Non-N-BPs decreased serum TC levels and increased serum TG levels. N-BPs did not affect serum lipid levels. Non-N-BPs had a beneficial effect on VC, and N-BPs had a beneficial effect on AS.

Cholesterol nanoarchaeosomes for alendronate targeted delivery as an anti-endothelial dysfunction agent

Sodium alendronate (ALN) is a very hydrosoluble and poorly permeable molecule used as an antiresorptive agent and with vascular anticalcifying capacity. Loaded into targeted nanovesicles, its anti-inflammatory activity may be amplified towards extra-osseous and noncalcified target cells, such as severely irritated vascular endothelium. Here cytotoxicity, mitochondrial membrane potential, ATP content, and membrane fluidity of human endothelial venous cells (HUVECs) were determined after endocytosis of ALN-loaded nanoarchaeosomes (nanoARC-Chol(ALN), made of polar lipids from Halorubrum tebenquichense: cholesterol 7:3 w/w, 166 ± 5 nm, 0.16 ± 0.02 PDI, -40.8 ± 5.4 mV potential, 84.7 ± 21 µg/mg ALN/total lipids, TL). The effect of nanoARC-Chol(ALN) was further assessed on severely inflamed HUVECs. To that aim, HUVECs were grown on a porous barrier on top of a basal compartment seeded either with macrophages or human foam cells. One lighter and one more pronounced inflammatory context was modelled by adding lipopolysaccharide (LPS) to the apical or the apical and basal compartments. The endocytosis of nanoARC-Chol(ALN), was observed to partly reduce the endothelial-mesenchymal transition of HUVECs. Besides, while 10 mg/mL dexamethasone, 7.6 mM free ALN and ALN-loaded liposomes failed, 50 μg/mL TL + 2.5 μg/mL ALN (i.e., nanoARC-Chol(ALN)) reduced the IL-6 and IL-8 levels by, respectively, 75% and 65% in the mild and by, respectively, 60% and 40% in the pronounced inflammation model. This is the first report showing that the endocytosis of nanoARC-Chol(ALN) by HUVECs magnifies the anti-inflammatory activity of ALN even under conditions of intense irritation, not only surpassing that of free ALN but also that of dexamethasone.

Distinguishable Colorimetric Biosensor for Diagnosis of Prostate Cancer Bone Metastases

Castration-resistant prostate cancer (PCa) causes severe bone metastasis (BM), which significantly increases mortality in men with PCa. Imaging tests and radiometric scanning require long analysis times, expensive equipment, specialized personnel, and a slow turnaround. New visualization technologies are expected to solve the above problems. Nonetheless, existing visualization techniques barely meet the urgency for precise diagnosis because the human eyes cannot recognize and capture even slight variations in visual information. By using dye differentiated superposition enhancement colorimetric biosensors, an effective method to diagnose prostate cancer bone metastases (PCa-BM) with excellent accuracy for naked-eye quantitative detection of alkaline phosphatase (ALP) is developed. The biomarker ALP specific hydrolytic product ascorbic acid can be detected by rhodamine derivatives (Rd) as gold nanobipyramids (Au NBPs) are deposited and grown. Color-recombining enhancement effects between Rd and Au NBPs significantly improved abundance. The 150 U L-1 threshold between normal and abnormal can be identified by color. And with color enhancement effect and double signal response, the ALP index is visually measured to diagnose PCa-BM and provide handy treatment recommendations. Additionally, the proposed colorimetric sensing strategy can be used to diagnose other diseases.

The bisphosphonates alendronate and zoledronate induce adaptations of aerobic metabolism in permanent human endothelial cells

Nitrogen-containing bisphosphonates (NBPs), compounds that are widely used in the treatment of bone disorders, may cause side effects related to endothelial dysfunction. The aim of our study was to investigate the effects of chronic 6-day exposure to two common bone-preserving drugs, alendronate and zoledronate, on endothelial function and oxidative metabolism of cultured human endothelial cells (EA.hy926). NBPs reduced cell viability, induced oxidative stress and a pro-inflammatory state and downregulated the prenylation-dependent ERK1/2 signaling pathway in endothelial cells. In addition, NBPs induced increased anaerobic respiration and slightly increased oxidative mitochondrial capacity, affecting mitochondrial turnover through reduced mitochondrial fission. Moreover, by blocking the mevalonate pathway, NBPs caused a significant decrease in the level of coenzyme Q10, thereby depriving endothelial cells of an important antioxidant and mitochondrial electron carrier. This resulted in increased formation of reactive oxygen species (ROS), upregulation of antioxidant enzymes, and impairment of mitochondrial respiratory function. A general decrease in mitochondrial respiration occurred with stronger reducing fuels (pyruvate and glutamate) in NBP-treated intact endothelial cells, and significantly reduced phosphorylating respiration was observed during the oxidation of succinate and especially malate in NBP-treated permeabilized endothelial cells. The observed changes in oxidative metabolism caused a decrease in ATP levels and an increase in oxygen levels in NBP-treated cells. Thus, NBPs modulate the energy metabolism of endothelial cells, leading to alterations in the cellular energy state, coenzyme Q10 redox balance, mitochondrial respiratory function, and mitochondrial turnover.

Antiresorptive Medication Use Is not Associated With Acute Cardiovascular Risk: An Observational Study

CONTEXT

Bisphosphonates have been reported to be cardioprotective in some, but not all, studies. It is unknown whether denosumab (Dmab) use protects against cardiovascular events (CVEs).

OBJECTIVE

To determine whether oral bisphosphonate (oBP) or Dmab use is associated with CVEs in persons with incident fracture.

METHODS

Participants with an incident minimal trauma fracture from the Sax Institute's 45 and Up Study, a population-based cohort from NSW, Australia, were followed between 2005/2009 and 2017. Questionnaire data were linked to hospital admissions (Admitted Patients Data Collection [APDC]) by the Centre for Health Record Linkage). Medicare Benefit Schedule (MBS) and Pharmaceutical Benefits Scheme (PBS) data sets were provided by Services Australia. Data was stored in a secure computing environment (Secure Unified Research Environment). Fractures, CVEs, and comorbidities were identified from the APDC and oBP and Dmab medication from the PBS. oBP and Dmab users were matched to never users (NoRx) by propensity scores. The main outcome measures were association between oBP and Dmab with CVE (acute myocardial infarction, unstable angina, cerebrovascular accident, and transient ischemic attack) and were determined using a stratified Cox's proportional hazards model.

RESULTS

There were 880 pairs of oBP and NoRx (616 women) and 770 pairs of Dmab and NoRx (615 women) followed for ∼4.3 years. CVE risk was similar for oBP and NoRx Hazard Ratios (HR) women, 0.88 [95% CI 0.65-1.18]; men, 1.07 [95% CI 0.72-1.57]). Similar findings were obtained for Dmab (Hazard Ratios (HR) women, 1.08 [95% CI 0.78-1.50]; men, 1.55 [95% CI 0.96-2.48]).

CONCLUSION

oBP and Dmab use was not associated with CVEs.

Vascular calcification: Molecular mechanisms and therapeutic interventions

Vascular calcification (VC) is recognized as a pathological vascular disorder associated with various diseases, such as atherosclerosis, hypertension, aortic valve stenosis, coronary artery disease, diabetes mellitus, as well as chronic kidney disease. Therefore, it is a life-threatening state for human health. There were several studies targeting mechanisms of VC that revealed the importance of vascular smooth muscle cells transdifferentiating, phosphorous and calcium milieu, as well as matrix vesicles on the progress of VC. However, the underlying molecular mechanisms of VC need to be elucidated. Though there is no acknowledged effective therapeutic strategy to reverse or cure VC clinically, recent evidence has proved that VC is not a passive irreversible comorbidity but an active process regulated by many factors. Some available approaches targeting the underlying molecular mechanism provide promising prospects for the therapy of VC. This review aims to summarize the novel findings on molecular mechanisms and therapeutic interventions of VC, including the role of inflammatory responses, endoplasmic reticulum stress, mitochondrial dysfunction, iron homeostasis, metabolic imbalance, and some related signaling pathways on VC progression. We also conclude some recent studies on controversial interventions in the clinical practice of VC, such as calcium channel blockers, renin-angiotensin system inhibitions, statins, bisphosphonates, denosumab, vitamins, and ion conditioning agents.

Vascular response to stress: Protective action of the bisphosphonate alendronate

BACKGROUND

Since several additional actions of bone bisphosphonates have been proposed, we studied the effect of the bisphosphonate alendronate (ALN) on the vascular response to environmental stress.

METHODS

Primary cultures of endothelial cells (EC) and vascular smooth muscle cells (VSMC) exposed to strained conditions were employed for experimental evaluation. After ALN treatment, cell migration, proliferation, and angiogenesis assays were performed. The participation of signal transduction pathways in the biochemical action of ALN was also assessed.

RESULTS

In VSMC cultures, ALN counteracted the stimulation of cellular migration elicited by the proinflammatory agent lipopolysaccharide (LPS) or by high levels of calcium and phosphorus (osteogenic medium). Indeed, ALN reduced the increase of VSMC proliferation evoked by the stressors. When LPS and osteogenic medium were added simultaneously, the enhancement of cell proliferation dropped to control values in the presence of ALN. The mechanism of action of ALN involved the participation of nitric oxide synthase, mitogen-activated protein kinase (MAPK), and protein kinase C (PKC) signaling pathways. The study revealed that ALN exhibits a proangiogenic action. On EC, ALN enhanced vascular endothelial growth factor (VEGF) synthesis, and induced capillary-like tube formation in a VEGF-dependent manner. The presence of vascular stress conditions (LPS or osteogenic medium) did not modify the proangiogenic action elicited by ALN.

CONCLUSION

The findings presented suggest an extra-bone biological action of ALN, which could contribute to the maintenance of vascular homeostasis avoiding cellular damage elicited by environmental stress.

Comparison of Vascular Morphometry in Jawbones and Long Bones: Micro-CT Study in a Rat Model Treated with Zoledronic Acid

The study was aimed at investigating the effect of zoledronic acid on vascular morphometry in jawbones and long bones on a rat model. Twenty-four skeletal mature Sprague-Dawley female rats were administered oncologic dose of zoledronic acid (ZA) or normal saline for 4 weeks and then subjected to tooth extraction on the mandible and maxilla and a bone defect creation on the femur. After the surgical procedures, ZA or saline treatment was continued until sacrifice at week 2, week 4, and week 8 postoperatively. Vascular perfusion with MICROFIL was performed on all the animals. Micro-CT analysis demonstrated a tendency of decreased vessel density and vessel number in ZA-treated groups but no statistical difference. In conclusion, the neovessel formation is suppressed but not significantly by ZA treatment, indicating that angiogenesis inhibition may contribute to the development of MRONJ but does not play a key role.

Benefits of Bisphosphonate Therapy: Beyond the Skeleton

PURPOSE OF REVIEW

Recent evidence from clinical trials and observational studies raises the possibility that bisphosphonate use might confer a lower risk of cardiovascular disease and cancer, resulting in a mortality benefit. This review summarizes clinical and preclinical studies examining the non-skeletal effects of bisphosphonates.

RECENT FINDINGS

Data from clinical trials are conflicting regarding whether or not bisphosphonates have beneficial effects on mortality, cardiovascular events, or cancer incidence. No clinical trials have assessed these outcomes as primary endpoints, and most trials were shorter than 4 years. Observational data suggest that bisphosphonate users may have lower mortality, delayed progression of vascular calcification and atherosclerotic burden, and reduced incidence of breast and colorectal cancer compared to non-users. Preclinical studies confirm that bisphosphonates can be taken up by macrophages and monocytes, and nitrogen-containing bisphosphonates have the ability to disrupt the mevalonate pathway within these cells. In this manner, bisphosphonates exert anti-atherogenic and anti-cancer effects. Bisphosphonates also appear to exert protective effects on vascular smooth muscle cells and endothelial cells and may have direct cytotoxic effects on cancer cells. The balance of evidence does not support bisphosphonate treatment for the primary purpose of improving non-skeletal outcomes, although appropriately designed controlled trials that further explore this possibility are both justified and required. Patients with skeletal indications for bisphosphonate therapy can be reassured that these agents are not associated with increased mortality, cardiovascular disease, or cancer incidence.

Alendronate alleviates the symptoms of experimental autoimmune encephalomyelitis

Nitrogen-containing bisphosphonates, such as alendronate, have been widely used to treat osteoporosis because they may target multiple signals in the mevalonate cascade. The present study evaluated the therapeutic effects of alendronate on experimental autoimmune encephalomyelitis (EAE), which is a prototypical autoimmune disease model. EAE was induced in C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein (MOG)_35-55 peptide. The mice were checked daily for clinical symptoms, such as paralysis, and the levels of inflammatory cytokines were analyzed using ELISA, western blot analyses, and immunohistochemistry. The daily oral administration of alendronate to EAE-induced mice significantly reduced the severity of paralysis and lowered T cell proliferation. Additionally, histopathological examinations confirmed that alendronate mitigated inflammation in the spinal cord after EAE induction, suppressed the infiltration of CD68-positive inflammatory cells, and reduced the production of various pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, as well as inducible nitric oxide synthase (iNOS). Furthermore, the alendronate-treated group exhibited a decrease in the number of iNOS-positive inflammatory cells compared to the vehicle-treated group. Taken together, the present results suggest that alendronate alleviated neuro-inflammation in the spinal cords of EAE-induced mice, which is an animal model of multiple sclerosis, possibly by inhibiting the downstream effects of the mevalonate cascade.

The Association of Oral Bisphosphonate Use With Mortality Risk Following a Major Osteoporotic Fracture in the United Kingdom: Population-Based Cohort Study

OBJECTIVES

Bisphosphonates (BPs) might have extra benefits in reducing mortality because of their anti-atherosclerotic effects, but studies reported conflicting results. We investigated the association between oral BP use and mortality risk following a major osteoporotic fracture (MOF) in the United Kingdom.

DESIGN

This was a population-based cohort study.

SETTING AND PARTICIPANTS

In total, 163,273 adults aged 50 years and older with an MOF between 2000 and 2018 from the Clinical Practice Research Datalink in the United Kingdom.

METHODS

Cox proportional hazards models were used to estimate the risk of all-cause mortality in current (0‒6 months), recent (7‒12 months), and past (>1 year) exposures to oral BPs after nonhip MOF and hip fracture. In addition, stratification by sex, BP type, and duration of follow-up was performed.

RESULTS

Compared with never users of oral BPs, current BP use was associated with a 7% higher all-cause mortality risk after nonhip MOF, whereas a 28% lower all-cause mortality risk was observed after hip fracture. Past BP exposure was associated with a 14% and 42% lower risk after nonhip MOF and hip fracture, respectively. When considering only the first 5 years of follow-up, mortality risk associated with current BP use was significantly lower for both fracture groups, and the greatest reduction in mortality risk was observed within the first year. Women had slightly lower risk compared with men.

CONCLUSIONS AND IMPLICATIONS

We found a slight increased risk of all-cause mortality with current BP exposure after a nonhip MOF; however, a protective effect was observed following a hip fracture. Both the timing and the effect size of an association based on the anti-atherosclerotic hypothesis of BPs are not supported by our results. The decreasing trend of the mortality risk with shorter durations of follow-up suggests that the observed association is likely due to unknown distortion or unknown pleiotropic properties of BPs.

Role of estrone on the regulation of osteoblastogenesis

Although estradiol bone contribution has been deeply studied, little is known about the action of estrone. We investigated the direct action of estrone on osteoblasts growth and differentiation, with focus on the biochemical mechanism displayed by the estrogen. Murine calvarial osteoblast cultures in vitro exposed to 10 nM estrone were employed. Estrone enhanced gene expression of the osteogenic differentiation marker, Runx2 mRNA (150% above control). The hormone significantly increased cell proliferation (38% above control), nitric oxide production (108% above control), alkaline phosphatase activity (50% above control), in addition to stimulation of extracellular matrix mineralization. Using specific antagonists, we found that the mechanism of action of estrone involves estrogen receptor, nitric oxide synthase and MAPK signalling pathways participation. The hormone acts by its own and probably not via conversion to estradiol, since 17 B HSD inhibition did not affect the hormonal action. This work shows a novel action of estrone on bone cells promoting osteoblastogenesis.

In vitro effects of progesterone and the synthetic progestin medroxyprogesterone acetate on vascular remodeling

In this work we tested the hypothesis whether progesterone (Pg) or the synthetic progestin medroxyprogesterone acetate (MPA) could be involved in the regulation of events involved in vascular remodeling. Results revealed an enhancement in the capillary-like tubes formation induced by both progestogens. Unlike MPA, Pg acts through VEGF, nitric oxide, PI3K and ERK1/2 signaling pathways. However, the MPA effect depends on platelet activation. Under stress conditions, the proangiogenic action of Pg and MPA was sustained. The progestogens exhibit the ability to prevent vascular smooth muscle cells (VSMC) osteogenic transdifferentiation. Besides this antiosteogenic action, on bone cells the progestogens induced osteoblast maturation and mineralization. The mechanism of action of both steroids on vascular and bone cells involves the participation of progesterone receptor. The data presented in this work provide evidence that the progestogens reduce osteogenic-like transdifferentiation of VSMC and promote angiogenesis with a slight different mechanism of action elicited by each steroid.

Natural and non-natural antioxidative compounds: potential candidates for treatment of vascular calcification

Vascular calcification (VC) is highly prevalent in patients with advanced age, or those with chronic kidney disease and diabetes, accounting for substantial global cardiovascular burden. The pathophysiology of VC involves active mineral deposition by transdifferentiated vascular smooth muscle cells exhibiting osteoblast-like behavior, building upon cores with or without apoptotic bodies. Oxidative stress drives the progression of the cellular phenotypic switch and calcium deposition in the vascular wall. In this review, we discuss potential compounds that shield these cells from the detrimental influences of reactive oxygen species as promising treatment options for VC. A comprehensive summary of the current literature regarding antioxidants for VC is important, as no effective therapy is currently available for this disease. We systematically searched through the existing literature to identify original articles investigating traditional antioxidants and novel compounds with antioxidant properties with regard to their effectiveness against VC in experimental or clinical settings. We uncovered 36 compounds with antioxidant properties against VC pathology, involving mechanisms such as suppression of NADPH oxidase, BMP-2, and Wnt/β-catenin; anti-inflammation; and activation of Nrf2 pathways. Only two compounds have been tested clinically. These findings suggest that a considerable opportunity exists to harness these antioxidants for therapeutic use for VC. In order to achieve this goal, more translational studies are needed.

Association of Alendronate and Risk of Cardiovascular Events in Patients With Hip Fracture

The risk of cardiovascular events (CVEs) with alendronate use in real-world hip fracture patients is unknown. This study aimed to investigate the risk of CVE with and without use of alendronate in patients with hip fracture. We conducted a retrospective cohort study using a population-wide database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with hip fracture from 2005 through 2013 were followed until November 6, 2016. Alendronate and other antiosteoporosis medications use during the study period were examined. We matched treated and nontreated patients based on time-dependent propensity score. The risks of cardiovascular mortality, myocardial infarction, and stroke between treatment groups were evaluated using conditional Cox regression stratified by match pairs. To examine the associations over time, outcomes were assessed at 1 year, 3 years, 5 years, and 10 years. Among 34,991 patients with newly diagnosed hip fracture, 4602 (13.2%) received antiosteoporosis treatment during follow-up. Physical functioning or survival prospect was not significantly different between treated and nontreated patients. A total of 4594 treated patients were matched with 13,568 nontreated patients. Results of Cox regression analysis revealed that alendronate was associated with a significantly lower risk of 1-year cardiovascular mortality (HR 0.33; 95% CI, 0.17 to 0.65) and incident myocardial infarction (HR 0.55; 95% CI, 0.34 to 0.89), whereas marginally significant reduction in risk of stroke was observed at 5 years and 10 years (HR at 5 years: 0.82; 95% CI, 0.67 to 1.00; p = 0.049; HR at 10 years: 0.83; 95% CI, 0.69 to 1.01; p = 0.065). The strength of the association declined over time but remained significant. Similar results were observed when all nitrogen-containing bisphosphonates (N-BPs) were analyzed together. These findings were robust in multiple sensitivity analyses. Additional studies in other population samples and randomized clinical trials may be warranted to further understand the relationship between use of various antiosteoporosis medication and risk of CVE in patients with hip fracture. © 2018 American Society for Bone and Mineral Research.