Cilnidipine, but not amlodipine, ameliorates osteoporosis in ovariectomized hypertensive rats through inhibition of the N-type calcium channel

The Role of Osteogenic Effect and Vascular Function in Bone Health in Hypertensive Rats: A Study of Anti-hypertensive and Hemorheologic Drugs

Vascular dysfunction contributes to the development of osteopenia in hypertensive patients, as decreased blood supply to bones results in tissue damage and dysfunction. The effect of anti-hypertensive medicines on bone mass in hypertensive individuals is inconclusive because of the varied mechanism of their action, and suggests that reducing blood pressure (BP) alone is insufficient to enhance bone mass in hypertension. Pentoxifylline (PTX), a hemorheological drug, improves blood flow by reducing blood viscosity and angiogenesis, also has an osteogenic effect. We hypothesized that improving vascular function is critical to increasing bone mass in hypertension. To test this, we screened various anti-hypertensive drugs for their in vitro osteogenic effect, from which timolol and hydralazine were selected. In adult female spontaneously hypertensive rats (SHRs), timolol and hydralazine did not improve vascular function and bone mass, but PTX improved both. In female SHR animals, PTX restored bone mass, strength and mineralization, up to the level of normotensive control rats. In addition, we observed lower blood vasculature in the femur of adult SHR animals, and PTX restored them. PTX also restored the bone vascular and angiogenesis parameters that had been impaired in OVX SHR compared to sham SHR. This study demonstrates the importance of vascular function in addition to increased bone mass for improving bone health as achieved by PTX without affecting BP, and suggests a promising treatment option for osteoporosis in hypertensive patients, particularly at-risk postmenopausal women.

The Role of Sympathetic Nerves in Osteoporosis: A Narrative Review

Osteoporosis, a systemic bone disease, is characterized by decreased bone density due to various reasons, destructed bone microstructure, and increased bone fragility. The incidence of osteoporosis is very high among the elderly, and patients with osteoporosis are prone to suffer from spine fractures and hip fractures, which cause great harm to patients. Meanwhile, osteoporosis is mainly treated with anti-osteoporosis drugs that have side effects. Therefore, the development of new treatment modalities has a significant clinical impact. Sympathetic nerves play an important role in various physiological activities and the regulation of osteoporosis as well. Therefore, the role of sympathetic nerves in osteoporosis was reviewed, aiming to provide information for future targeting of sympathetic nerves in osteoporosis.

Do antihypertensive medications effect the mandibular cortical bone thickness? A study using cone beam computed tomography images

OBJECTIVE

The aim of this study was to measure the association between antihypertensive medication use and mandibular cortical thickness.

STUDY DESIGN

This retrospective cross-sectional study was comprised of a study sample of 169 patients aged 40 to 69. Cone beam computed tomography scans were examined. The buccal cortical thickness of the mandibular ramus was measured. Participants were separated into the control or study group based on use of antihypertensive medications. The predictor variable was the use of antihypertensive medications. The primary outcome variable was cortical thickness of the mandible. Age was identified as a covariate affecting the outcome variable. The data was analyzed with a one-way analysis of covariance (ANCOVA) to remove the effect of age on the outcome variable. The groups were subdivided based on the sex of the patient.

RESULTS

The study sample was composed of 169 patients with a mean age of 52.1, and 54% were female. There were 67 patients in the antihypertensive group (39.6%). A mean difference of 0.21 mm was found (P = .0010, 95% CI 0.09, 0.34 mm). The difference persisted after adjusting for age with one-way ANCOVA testing (P < .001).

CONCLUSIONS

This study suggests that there may be an association between antihypertensive use and mandibular cortical thickness. Age may be an effect modifier with the effect increasing in older patients.

Therapeutic Effect of Benidipine on Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) is an intractable disease that is typically observed in patients with osteoporosis or tumors that have been treated with either bisphosphonate (BP) or antiangiogenic medicine. The mechanism of MRONJ pathogenesis remains unclear, and no effective definitive treatment modalities have been reported to date. Previous reports have indicated that a single injection of benidipine, an antihypertensive calcium channel blocker, in the vicinity of a tooth extraction socket promotes wound healing in healthy rats. The present study was conducted to elucidate the possibility of using benidipine to promote the healing of MRONJ-like lesions. In this study, benidipine was administered near the site of MRONJ symptom onset in a model rat, which was then sacrificed two weeks after benidipine injection, and analyzed using histological sections and CT images. The analysis showed that in the benidipine groups, necrotic bone was reduced, and soft tissue continuity was recovered. Furthermore, the distance between epithelial edges, length of necrotic bone exposed in the oral cavity, necrotic bone area, and necrotic bone ratio were significantly smaller in the benidipine group. These results suggest that a single injection of benidipine in the vicinity of MRONJ-like lesions can promote osteonecrotic extraction socket healing.

Differential impact of antihypertensive drugs on cardiovascular remodeling: a review of findings and perspectives for HFpEF prevention

Heart failure (HF) is an important health problem worldwide whose stages have traditionally been classified from A to D. In addition, HF can be categorized as that with preserved ejection fraction (HFpEF) and that with reduced ejection fraction (HFrEF). Hypertension and arterial stiffness in stage A HF are major drivers of the progression to left ventricular hypertrophy (LVH), a criterion of stage B HF. Although the pathogenesis of HFpEF is heterogeneous, affected patients tend to be older than HFrEF patients and have a greater prevalence of hypertension, which is closely associated with arterial stiffness and LVH. Thus, to treat HFpEF, the optimal intervention for improving prognosis is an aggressive approach to early-stage, i.e., Stage A and B, HF. This paper reviews the findings on arterial stiffness and LVH using conventional antihypertensive drugs such as angiotensin receptor II blockers (ARBs) and a new drug class for HF, ARB/neprilysin inhibitor (ARNi). Previous studies have suggested that the combination of an ARB with an L-T-type calcium channel blocker might be recommended for the improvement of arterial stiffness and regression of LVH. More recent research has shown that ARNi also improves central BP, which leads to a reduced afterload and a significant reduction in LVH. For optimal treatment of HFpEF, drug therapy should directly address arterial stiffness as well as hypertension.

Tetrandrine Inhibits Titanium Particle-Induced Inflammatory Osteolysis through the Nuclear Factor-κB Pathway

Peri-implant osteolysis (PIO) and the subsequent aseptic loosening are the main reasons for artificial joint implant failure. Existing methods for treating aseptic loosening are far from satisfactory, necessitating advanced drug exploration. This study is aimed at investigating the effect and underlying mechanism of tetrandrine (Tet) on inflammatory osteolysis. We established a Ti particle-induced inflammatory osteolysis mouse model and administered Tet or an equal volume of phosphate-buffered saline (PBS). Two weeks later, specimens were collected. Histological staining showed that Tet administration inhibited Ti-stimulated osteolysis. Tartrate-resistant acid phosphate (TRAP) staining and transmission electron microscopy (TEM) demonstrated that osteoclast formation was remarkably inhibited in the groups treated with Tet in a dose-dependent manner. In addition, relevant inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6) were also significantly reduced in the calvaria of the Tet-treated groups. Exposure of receptor activator for nuclear factor-κB ligand- (RANKL-) induced bone marrow-derived macrophages (BMMs) and RAW264.7 cells to Tet significantly reduced osteoclast formation, F-actin ring formation, bone resorption, and the expression of relevant genes (matrix metallopeptidase 9 (MMP-9), TRAP, and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1)) during osteoclastogenesis in vitro. Mechanistic studies using Western blotting demonstrated that Tet inhibited the nuclear factor (NF)-κB signaling pathway by decreasing the phosphorylation of inhibitor of NF-κB α (IκBα) and p65, which play important roles in osteoclast formation. Collectively, our data indicate that Tet suppressed Ti-induced inflammatory osteolysis and osteoclast formation in mice, suggesting that Tet has the potential to be developed to treat and prevent wear particle-induced inflammatory osteolysis.

Cav 1.2 regulates osteogenesis of bone marrow-derived mesenchymal stem cells via canonical Wnt pathway in age-related osteoporosis

Aims

Age‐related bone mass loss is one of the most prevalent diseases that afflict the elderly population. The decline in the osteogenic differentiation capacity of bone marrow‐derived mesenchymal stem cells (BMMSCs) is regarded as one of the central mediators. Voltage‐gated Ca²⁺ channels (VGCCs) play an important role in the regulation of various cell biological functions, and disruption of VGCCs is associated with several age‐related cellular characteristics and systemic symptoms. However, whether and how VGCCs cause the decreased osteogenic differentiation abilities of BMMSCs have not been fully elucidated.

Methods

Voltage‐gated Ca²⁺ channels related genes were screened, and the candidate gene was determined in several aging models. Functional role of determined channel on osteogenic differentiation of BMMSCs was investigated through gain and loss of function experiments. Molecular mechanism was explored, and intervention experiments in vivo and in vitro were performed.

Results

We found that Ca_v1.2 was downregulated in these aging models, and downregulation of Ca_v1.2 in Zmpste24−/− BMMSCs contributed to compromised osteogenic capacity. Mechanistically, Ca_v1.2 regulated the osteogenesis of BMMSCs through canonical Wnt/β‐catenin pathway. Moreover, upregulating the activity of Ca_v1.2 mitigated osteoporosis symptom in Zmpste24−/− mice.

Conclusion

Impaired osteogenic differentiation of Zmpste24−/− BMMSCs can be partly attributed to the decreased Ca_v1.2 expression, which leads to the inhibition of canonical Wnt pathway. Bay K8644 treatment could be an applicable approach for treating age‐related bone loss by ameliorating compromised osteogenic differentiation capacity through targeting Ca_v1.2 channel.

Effect of a Single Injection of Benidipine-Impregnated Biodegradable Microcarriers on Bone and Gingival Healing at the Tooth Extraction Socket

Objective: A dihydropyridine-type calcium channel blocker, benidipine (BD), is extensively used in hypertension therapy. In vitro study reported BD promoting bone metabolism. We evaluated the effect of sustained release of BD-loaded poly(lactic-co-glycolic acid) (PLGA) microcarriers on the promotion of bone and gingival healing at an extraction socket in vivo. In addition, the effect of BD on osteoblasts, osteocytes, fibroblasts, and epithelial cells was evaluated in vitro. Approach: The maxillary first molar of rats was extracted. Next, PLGA microcarriers containing BD were directly injected into the gingivobuccal fold as a single dose. After injection, bone and soft-tissue healing was histologically evaluated. Effect of BD on proliferation, migration, and gene expression of gingival and bone cell was also examined in vitro. Results: After tooth extraction, BD significantly augmented bone volume and density, and also epithelial wound healing. During in vitro studies, BD promoted significant proliferation and migration of fibroblasts and epithelial cells. Real-time RT-PCR revealed that BD upregulated messenger RNA expression of Ahsg (alpha 2-HS glycoprotein) and Csf2 (colony-stimulating factor 2) in osteoblasts. Innovation: The prevention of bone and soft-tissue reduction associated with tooth extraction has been eagerly anticipated in the field of dentistry. This study first reported the effect of BD on extraction socket healing. Conclusion: A single dose of topically administered BD-loaded PLGA microcarriers promoted bone and soft-tissue healing at the extraction site of tooth.

Antioxidative 1,4-Dihydropyridine Derivatives Modulate Oxidative Stress and Growth of Human Osteoblast-Like Cells In Vitro

Oxidative stress has been implicated in pathophysiology of different human stress- and age-associated disorders, including osteoporosis for which antioxidants could be considered as therapeutic remedies as was suggested recently. The 1,4-dihydropyridine (DHP) derivatives are known for their pleiotropic activity, with some also acting as antioxidants. To find compounds with potential antioxidative activity, a group of 27 structurally diverse DHPs, as well as one pyridine compound, were studied. A group of 11 DHPs with 10-fold higher antioxidative potential than of uric acid, were further tested in cell model of human osteoblast-like cells. Short-term combined effects of DHPs and 50 µM H₂O₂ (1-h each), revealed better antioxidative potential of DHPs if administered before a stressor. Indirect 24-h effect of DHPs was evaluated in cells further exposed to mild oxidative stress conditions induced either by H₂O₂ or tert-butyl hydroperoxide (both 50 µM). Cell growth (viability and proliferation), generation of ROS and intracellular glutathione concentration were evaluated. The promotion of cell growth was highly dependent on the concentrations of DHPs used, type of stressor applied and treatment set-up. Thiocarbatone III-1, E2-134-1 III-4, Carbatone II-1, AV-153 IV-1, and Diethone I could be considered as therapeutic agents for osteoporosis although further research is needed to elucidate their bioactivity mechanisms, in particular in respect to signaling pathways involving 4-hydroxynoneal and related second messengers of free radicals.

Effects of Amlodipine on Bone Metabolism in Orchidectomised Spontaneously Hypertensive Rats

Spontaneously hypertensive rats (SHR) represent a model of essential hypertension. We studied the effect of amlodipine (AML) on bone markers, bone mineral density (BMD), and biomechanical properties of osteopenic bone induced by orchidectomy in male SHR. Rats were allocated to 3 groups and were sacrificed after 12 weeks: sham-operated control; orchidectomised control; and orchidectomised receiving a diet supplemented with AML. Indicators of bone turnover were assessed in bone homogenate, BMD was measured by dual energy X-ray absorptiometry, and the femurs were subjected to biomechanical testing. Long-term AML administration does not have a negative impact on bone metabolism and density in male SHR.

INF-γ encoding plasmid administration triggers bone loss and disrupts bone marrow microenvironment

IFN-γ is a pleotropic cytokine produced in the bone microenvironment. Although IFN-γ is known to play a critical role on bone remodeling, its function is not fully elucidated. Consistently, outcomes on the effects of IFN-γ recombinant protein on bone loss are contradictory among reports. In our work we explored, for the first time, the role of IFN-γ encoding plasmid (pIFN-γ) in a mouse model of osteopenia induced by ovariectomy and in the sham-operated counterpart to estimate its effects in skeletal homeostasis. Ovariectomy produced a dramatic decrease of bone mineral density (BMD). pINF-γ injected mice showed a pathologic bone and bone marrow phenotype; the disrupted cortical and trabecular bone microarchitecture was accompanied by an increased release of pro-inflammatory cytokine by bone marrow cells. Moreover, mesenchymal stem cells' (MSCs) commitment to osteoblast was found impaired, as evidenced by the decline of osterix-positive (Osx⁺) cells within the mid-diaphyseal area of femurs. For instance, a reduction and redistribution of CXCL12 cells have been found, in accordance with bone marrow morphological alterations. As similar effects were observed both in sham-operated and in ovariectomized mice, our studies proved that an increased IFN-γ synthesis in bone marrow might be sufficient to induce inflammatory and catabolic responses even in the absence of pathologic predisposing substrates. In addition, the obtained data might raise questions about pIFN-γ's safety when it is used as vaccine adjuvant.

The effects of amlodipine and platelet rich plasma on bone healing in rats

Aim

The aim of this study was to evaluate the effects of calcium channel blocker (CCB) amlodipine (AML), platelet rich plasma (PRP), and a mixture of both materials on bone healing.

Materials and methods

Fifty-six male Wistar rats were randomly divided into four groups: group A, tibia defect model with no treatment; group B, tibia defect model treated with AML, 0.04 mg daily by oral gavage; group C, tibia defect model treated with local PRP; group D, tibia defect model treated with local PRP and AML, 0.04 mg daily by oral gavage.

Results

At day 21, bone healing was significantly better in groups C and D compared to group A (P<0.05), but comparisons showed no statistically significant difference in group B (P>0.05). At day 30, groups B and C showed no statistically significant difference (P>0.05) compared to group A, but bone healing in group D was significantly better than in group A (P<0.05). Statistically, AML did not affect alkaline phosphatase (ALP) activity at 21 and 30 days (P>0.05), but PRP and AML + PRP increased ALP activity statistically (P<0.05).

Conclusion

It can be concluded that AML had neither a positive nor a negative effect on bone healing, but when used in combination with PRP, it may be beneficial.

Effect of angiotensin II receptor blocker, olmesartan, on turnover of bone metabolism in bedridden elderly hypertensive women with disuse syndrome

AIMS

Although recent studies suggest that several antihypertensive drugs could reduce the risk of bone fracture, it is still unclear how these drugs act on bone remodeling, especially in elderly women with severe osteoporosis with disuse syndrome. In the present study, we investigated the effects of a calcium channel blocker (CCB) and an angiotensin II receptor blocker (ARB) on bone metabolism in elderly bedridden women with hypertension and disuse syndrome.

METHODS

Elderly bedridden women (aged >75 years) receiving antihypertensive therapy treated with CCB were recruited in the present study. The participants were divided into two groups--CCB group and ARB group--and followed up to 12 months.

RESULTS

Markers of bone resorption were markedly increased, suggesting accelerated bone resorption in the participants of the present study. In the follow-up period, the patients treated with a CCB showed a significant decrease in bone mineral density in a time-dependent manner, accompanied by a significant increase in bone resorption markers, whereas treatment with olmesartan inhibited bone loss, associated with attenuation of increased bone resorption markers. Bone mineral density of femoral neck in the CCB group was significantly lower than that in the ARB group at 6 months.

CONCLUSION

The present study showed inhibitory effects of an ARB on bone resorption in hypertensive patients with accelerated bone resorption, such as elderly bedridden women, and indicated an important role of the renin-angiotensin system in bone metabolism. In elderly hypertensive patients, ARB might be expected to have additional beneficial potential to maintain bone health in bedridden patients.

Amlodipine increases vitamin D levels more than valsartan in newly diagnosed hypertensive patients: pointing to an additional effect on bone metabolism or a novel marker of inflammation?

Hypertension is a major challenge for public health. Appropriate antihypertensive treatment seem to provide a better life with lower morbidity and mortality rates. Another pathologic condition, osteoporosis, mainly affects postmenouposal women, and constitutes a growing body of risks after a particular age. As bone is a dynamic organ system that is directly related to calcium and phosphor metabolism, imbalance in these two parameters upon aging or menopause finally may lead to osteoporosis. Today, both osteoporosis and high blood pressure are major morbidities, especially in the elderly population. There are some intriguing results on the effects of antihypertensive agents on bone metabolism in the literature. In this study, we aimed to investigate the effects of widely used antihypertensive agents, valsartan and amlodipine on vitamin D levels in newly diagnosed hypertensive population. We found that amlodipine increased vitamin D levels significantly in patients with a newly diagnosed hypertension on a 12-week treatment duration compared to valsartan.

Involvement of N-type Ca(2+) channels in the fibrotic process of the kidney in rats

N-type Ca(2+) channels are densely distributed in sympathetic nerves that innervate renal tubules. However, the role of N-type Ca(2+) channels in renal fibrosis remains unknown. To address this issue, we examined the difference between the effects of amlodipine (an L-type Ca(2+) channel blocker) and cilnidipine (a dual L/N-type Ca(2+) channel blocker) on fibrotic changes using a rat unilateral ureteral obstruction (UUO) model. The expression of both L-type and N-type Ca(2+) channels was significantly upregulated in UUO kidneys compared with that in contralateral kidneys. There were no significant differences in mean blood pressure among the rats tested. Both amlodipine and cilnidipine significantly attenuated fibrotic changes in UUO kidneys. The antifibrotic effect of cilnidipine was more potent than that of amlodipine. Amlodipine as well as cilnidipine reduced type III collagen deposition, α-smooth muscle actin (α-SMA) expression, and interstitial cell proliferation. In addition, cilnidipine significantly reduced deposition of type I collagen and macrophage infiltration in UUO kidneys. With the use of in vivo bromodeoxyuridine labeling, label-retaining cells (LRCs) were identified as a population of tubular cells that participate in epithelial-mesenchymal transition after UUO. Some LRCs migrated into the interstitium, expressed α-SMA and vimentin, and produced several extracellular matrixes in UUO kidneys. The number of interstitial LRCs was significantly decreased by cilnidipine but not amlodipine. These data suggest that N-type Ca(2+) channels contribute to multiple steps of renal fibrosis, and its blockade may thus be a useful therapeutic approach for prevention of renal fibrosis.