Short-term glucocorticoid excess blunts abaloparatide-induced increase in femoral bone mass and strength in mice

Analyzing the factors associated with efficacy among teriparatide treatment in postmenopausal women with osteoporosis

BACKGROUND

Teriparatide (TPTD) is a widely used anabolic agent for the treatment of osteoporosis. Several factors have been identified to be related to bone mineral density (BMD) increase in anti-osteoporosis treatment with other agents; however, there has been no systematic analysis to summarize the associated determinants of BMD reaction to daily teriparatide treatment.

METHODS

In this retrospective study, we performed a comprehensive investigation involving not only clinical data but also several relevant lifestyle factors to be examined for their potential contribution to BMD response. This post-hoc analysis included 258 post-menopaused patients with osteoporosis who received TPTD at 20 µg/day for 12 months. Univariate and multivariate analyses were conducted to distinguish the response variables of lumbar spine (LS) BMD transformation, the principal outcome measure of efficacy, from the baseline at 12 months.

RESULTS

Twelve months of TPTD treatment resulted in an absolute 0.39 ± 0.37 increase in T-score of LS BMD. Gastrointestinal disease, prior bisphosphonate or glucocorticoid treatment, no vitamin K2 supplementation, low levels of serum 25(OH)D and PINP, weak increment of PINP and β-CTX at 3 months, unhealthy lifestyle (excessive smoking, tea, coffee, and drinking), vegetarian diet pattern, low ALT level, and high BMD at baseline were determined by univariate analyses to be related to the weak reaction of TPTD treatment (P < 0.10). In the multiple regression model, postmenopausal women with vitamin K2 supplementation, higher baseline serum 25(OH)D level, and higher PINP concentration at 3 months indicated a good reaction of LS BMD at 12 months (P < 0.05). Patients with gastrointestinal disease, prior bisphosphonate and glucocorticoid treatment, vegetarian diet pattern, and higher baseline BMD were significantly more likely to have a lower absolute LS BMD response compared to patients without these characteristics (P < 0.05). Further analysis confirmed the negative effect of unhealthy lifestyle on TPTD treatment.

CONCLUSION

Our results emphasize the significance of a comprehensive assessment of clinical or lifestyle-related characteristics of postmenopausal women with osteoporosis in the management of TPTD therapy in routine care.

Sarcopenia and treatment failure in inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND

The association between sarcopenia and treatment outcomes in inflammatory bowel disease (IBD) is currently a subject of controversy.

METHODS

A systematic search was performed of PubMed, Embase, Web of Science, and the Cochrane Library for studies published until April 2023. The quality assessment of each included study was performed using the Newcastle-Ottawa Scale.

RESULTS

Seventeen studies were included with 2,895 IBD patients. Sarcopenia exhibited an increased risk of treatment failure (OR=2.00, 95% CI: 1.43-2.79) and notably increased the need for surgery (OR=1.54,95%CI:1.06-2.23) as opposed to a pharmacologic treatment plan change (OR=1.19, 95% CI:0.71-2.01) among IBD patients. However, no significant association was found between sarcopenia and treatment failure in corticosteroid (OR=1.21, 95% CI: 0.55-2.64) or biologic agent (OR=1.65, 95% CI: 0.93-2.92) cohorts. Sarcopenia was also linked to elevated treatment failure risks in patients with Crohn's disease (OR=1.82, 95% CI: 1.15-2.90) and those diagnosed with ulcerative colitis (OR=2.55, 95% CI: 1.05-6.21), spanning both Asian (OR=1.88, 95% CI: 1.29-2.74) and non-Asian regions (OR=2.17, 95% CI: 1.48-3.18).

CONCLUSIONS

Sarcopenia was considered a novel marker for use in clinical practice to predict treatment failure, specifically, the need for surgery in IBD patients. This distinct cohort necessitates clinical attention and tailored care strategies.

Glucocorticoid-induced osteoporosis: an overview with focus on its prevention and management

The widespread use of glucocorticoids (GCs) contributes to the effective management of several diseases and conditions. However, it comes at a price in the case of the bones causing glucocorticoid-induced osteoporosis (GIOP), the most common cause of secondary osteoporosis and fractures. Several scientific societies have issued comprehensive guidelines on the optimal management of patients receiving GCs with the aim of providing answers to three fundamental questions, namely, whom to treat, when to treat, and how to treat. Both common ground and different approaches exist among them. General preventive measures should start along with GC initiation, and the duration of GC therapy should be limited to the minimal effective range. A pre-existing fracture, age, gender, menopausal status, dose, and duration of GC treatment are key factors in the decision to initiate antiosteoporotic medication. Oral bisphosphonates are typically regarded as the first-line treatment choice for GIOP partly due to their cost-effectiveness. Denosumab is another valid option, but an "exit strategy" should be considered before its initiation due to the risk of rebound-associated vertebral fractures upon its discontinuation. Since impaired bone formation represents the main mechanism by which GCs negatively affect skeletal health, osteoanabolic therapies appear to be pathophysiologically the more appropriate and appealing option, although cost considerations currently limit their use to selected severe cases. Regardless of the agent selected to mitigate the impact of GCs on the skeleton, what is most crucial is that the treating physician correctly stratifies the risk and intervenes at the right time.

Pharmaceutical treatment of bone loss: From animal models and drug development to future treatment strategies

Animal models are fundamental to advance our knowledge of the underlying pathophysiology of bone loss and to study pharmaceutical countermeasures against it. The animal model of post-menopausal osteoporosis from ovariectomy is the most widely used preclinical approach to study skeletal deterioration. However, several other animal models exist, each with unique characteristics such as bone loss from disuse, lactation, glucocorticoid excess, or exposure to hypobaric hypoxia. The present review aimed to provide a comprehensive overview of these animal models to emphasize the importance and significance of investigating bone loss and pharmaceutical countermeasures from perspectives other than post-menopausal osteoporosis only. Hence, the pathophysiology and underlying cellular mechanisms involved in the various types of bone loss are different, and this might influence which prevention and treatment strategies are the most effective. In addition, the review sought to map the current landscape of pharmaceutical countermeasures against osteoporosis with an emphasis on how drug development has changed from being driven by clinical observations and enhancement or repurposing of existing drugs to today's use of targeted anti-bodies that are the result of advanced insights into the underlying molecular mechanisms of bone formation and resorption. Moreover, new treatment combinations or repurposing opportunities of already approved drugs with a focus on dabigatran, parathyroid hormone and abaloparatide, growth hormone, inhibitors of the activin signaling pathway, acetazolamide, zoledronate, and romosozumab are discussed. Despite the considerable progress in drug development, there is still a clear need to improve treatment strategies and develop new pharmaceuticals against various types of osteoporosis. The review also highlights that new treatment indications should be explored using multiple animal models of bone loss in order to ensure a broad representation of different types of skeletal deterioration instead of mainly focusing on primary osteoporosis from post-menopausal estrogen deficiency.

Molecular Complex of HSIM-loaded Polymeric Nanoparticles: Potential Carriers in Osteoporosis

BACKGROUND

Statins, especially simvastatin promote bone formation by stimulating the activity of osteoblasts and suppressing osteoclast activity via the BMP-Smad signaling pathway. Statins present the liver first-pass metabolism. This study attempts to fabricate and evaluate simvastatin functionalized hydroxyapatite encapsulated in poly(lactic-co-glycolic) acid (PLGA) nanoparticles (HSIM-PLGA NPs) administered subcutaneously with sustained release properties for effective management of osteoporosis.

METHODS

Simvastatin functionalized hydroxyapatite (HSIM) was prepared by stirring and validated by docking studies, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Further, HSIM-loaded PLGA nanoparticles (HSIM-PLGA NPs) were developed via the solvent emulsification method. The nanoparticles were evaluated for zeta potential, particle size, entrapment efficiency, stability studies, and in vitro drug release studies. in vitro binding affinity of nanoparticles for hydroxyapatite was also measured. Bone morphology and its effect on bone mineral density were examined by using a glucocorticoid-induced osteoporosis rat model.

RESULTS

The optimized nanoparticles were found to be amorphous and showed no drug-polymer interaction. The particle size of formulated nanoparticles varied from 196.8 ± 2.27nm to 524.8 ± 5.49 nm and the entrapment efficiency of nanoparticles varied from 41.9 ± 3.44% to 70.8 ± 4.46%, respectively. The nanoparticles showed sustained release behaviour (75% in 24 hr) of the drug followed by non-fickian drug release. The nanoparticles exhibited high binding affinity to bone cell receptors, increasing bone mineral density. A significant difference in calcium and phosphorous levels was observed in disease and treatment rats. Porous bone and significant improvement in porosity were observed in osteoporotic rats and treated rats, respectively (P < 0.05).

CONCLUSION

Bone-targeting nanoparticles incorporating functionalized simvastatin can target bone. Thus, in order to distribute simvastatin subcutaneously for the treatment of osteoporosis, the developed nanoparticles may act as a promising approach.

Treatment of cystic fibrosis related bone disease

The advent of highly effective CFTR modulator therapies has slowed the progression of pulmonary complications in people with cystic fibrosis. There is increased interest in cystic fibrosis bone disease (CFBD) due to the increasing longevity of people with cystic fibrosis. CFBD is a complex and multifactorial disease. CFBD is a result of hypomineralized bone leading to poor strength, structure and quality leading to susceptibility to fractures. The development of CFBD spans different age groups. The management must be tailored to each group with nuance and based on available guidelines while balancing therapeutic benefits to risks of long-term use of bone-active medication. For now, the mainstay of treatment includes bisphosphonates. However, the long-term effects of bisphosphonate treatment in people with CF are not fully understood. We describe newer agents available for osteoporosis treatment. Still, the lack of data behooves trials of monoclonal antibodies treatments such as Denosumab and Romozosumab and anabolic bone therapy such as teriparatide and Abaloparatide. In this review, we also summarize screening and non-pharmacologic treatment of CFBD and describe the various options available for the pharmacotherapy of CFBD. We address the prospect of CFTR modulators on bone health while awaiting long-term trials to describe the effects of these medications on bone health.

Inhibition of Cdk5 Ameliorates Skeletal Bone Loss in Glucocorticoid-Treated Mice

Glucocorticoids (GCs) are widely used to treat inflammatory diseases. However, their long-term use leads to glucocorticoid-induced osteoporosis, increasing morbidity and mortality. Both anabolic and anti-resorptive drugs are used to counteract GC-induced bone loss, however, they are expensive and/or have major side effects. Therefore, identifying new targets for cost-effective, small-molecule inhibitors is essential. We recently identified cyclin-dependent kinase 5 (Cdk5) as a suppressor of osteoblast differentiation and showed that its inhibition with roscovitine promoted osteoblastogenesis, thus improving the skeletal bone mass and fracture healing. Here, we assessed whether Cdk5 knockdown or inhibition could also reverse the GC-mediated suppression of osteoblast differentiation, bone loss, and fracture healing. We first demonstrated that Cdk5 silencing abolished the dexamethasone (Dex)-induced downregulation of alkaline phosphatase (Alp) activity, osteoblast-specific marker gene expression (Runx2, Sp7, Alpl, and Bglap), and mineralization. Similarly, Cdk5 inhibition rescued Dex-induced suppression of Alp activity. We further demonstrated that Cdk5 inhibition reversed prednisolone (Pred)-induced bone loss in mice, due to reduced osteoclastogenesis rather than improved osteoblastogenesis. Moreover, we revealed that Cdk5 inhibition failed to improve Pred-mediated impaired fracture healing. Taken together, we demonstrated that Cdk5 inhibition with roscovitine ameliorated GC-mediated bone loss but did not reverse GC-induced compromised fracture healing in mice.

Evaluation of an Ionic Calcium Fiber Supplement and Its Impact on Bone Health Preservation in a Dietary Calcium Deficiency Mice Model

ionic calcium can help in the prevention of the process of osseous decalcification. This study aimed to evaluate the physicochemical properties and toxic effects of ionic calcium-fiber supplement (ICa+) and its impact on bone health preservation in mice C57/BL6 fed a calcium-deficient diet. Physicochemical properties include FTIR, apparent calcium solubility estimated by the calcium ratio obtained by ionization chromatography and atomic absorption. In vitro genotoxicity and cytotoxicity of the ICa+ were assessed. Twenty-five 7-week-old C57/BL6 mice were fed calcium-free diet (CFD) or CFD plus CaCO3 (1.33 mg Ca) or CFD plus ICa+ (1.33–6.66 mg Ca) for six weeks. After that, bone mass and microstructure parameters were assessed. Histological staining was performed to determine calcium deposits. ICa+ (100%) exhibited an apparent calcium solubility higher than CaCO3 (12.3%). ICa+ showed no cytotoxic and genotoxic in vitro activities. Histomorphometry analysis showed that the ICa+ treated group displayed a higher trabecular number than the trabecular space. Also, the ratio BV/TV was increased compared with all treatments. Ionic calcium-fiber supplementation prevents bone deterioration compared to mice fed a calcium-deficient diet.

Effect of Acetazolamide and Zoledronate on Simulated High Altitude-Induced Bone Loss

Exposure to hypobaric hypoxia at high altitude puts mountaineers at risk of acute mountain sickness. The carbonic anhydrase inhibitor acetazolamide is used to accelerate acclimatization, when it is not feasible to make a controlled and slow ascend. Studies in rodents have suggested that exposure to hypobaric hypoxia deteriorates bone integrity and reduces bone strength. The study investigated the effect of treatment with acetazolamide and the bisphosphonate, zoledronate, on the skeletal effects of exposure to hypobaric hypoxia. Eighty 16-week-old female RjOrl : SWISS mice were divided into five groups: 1. Baseline; 2. Normobaric; 3. Hypobaric hypoxia; 4. Hypobaric hypoxia + acetazolamide, and 5. Hypobaric hypoxia + zoledronate. Acetazolamide was administered in the drinking water (62 mg/kg/day) for four weeks, and zoledronate (100 μg/kg) was administered as a single subcutaneous injection at study start. Exposure to hypobaric hypoxia significantly increased lung wet weight and decreased femoral cortical thickness. Trabecular bone was spared from the detrimental effects of hypobaric hypoxia, although a trend towards reduced bone volume fraction was found at the L4 vertebral body. Treatment with acetazolamide did not have any negative skeletal effects, but could not mitigate the altitude-induced bone loss. Zoledronate was able to prevent the altitude-induced reduction in cortical thickness. In conclusion, simulated high altitude affected primarily cortical bone, whereas trabecular bone was spared. Only treatment with zoledronate prevented the altitude-induced cortical bone loss. The study provides preclinical support for future studies of zoledronate as a potential pharmacological countermeasure for altitude-related bone loss.

Abaloparatide: A review of preclinical and clinical studies

Osteoporosis is a debilitating disease characterized by reduced bone mineral density and an increased risk of fractures. This review aims to provide a comprehensive overview of, and map current knowledge, obtained from preclinical and clinical studies of the osteoanabolic agent abaloparatide. PubMed and Embase were meticulously searched from inception to May 4, 2021.178 titles and abstracts were screened, and 57 full-text articles were assessed for inclusion. A total of 55 articles were included; 5 (9%) in vitro studies, 21 (38%) in vivo studies, and 29 (53%) clinical studies. Preclinical in vitro studies have demonstrated receptor conformation preferability, structural insights into the receptor-agonist complex, and proliferative effects of abaloparatide on osteoblasts. Preclinical studies have shown abaloparatide to be similarly effective to teriparatide using comparable doses in both ambulating mice and rats challenged by disuse. Other animal studies have reported that abaloparatide effectively mitigates or prevents bone loss from ovariectomy, orchiectomy, and glucocorticoids and improves fracture healing. The pivotal clinical study ACTIVE demonstrated 18 months of treatment with abaloparatide substantially increase bone mineral density and reduce fracture risk in post-menopausal women compared with placebo. The extension study ACTIVExtend highlighted that subsequent treatment with alendronate sustained the bone gained by abaloparatide treatment and the reduced fracture risk for up to two years. Post-hoc sub-group analyses have also supported the efficacy and safety of abaloparatide treatment independent of various baseline risk factors. In conclusion, mounting evidence from preclinical and clinical studies has uniformly reported that abaloparatide increases bone mineral density and reduces fracture risk.