Calcitonin therapy in osteoporosis

Molecular mechanisms and treatment strategies for estrogen deficiency-related and glucocorticoid-induced osteoporosis: a comprehensive review

Osteoporosis, a debilitating condition characterized by reduced bone mass and increased fracture risk, is notably influenced by estrogen deficiency and glucocorticoid treatment. This comprehensive review elucidates the molecular mechanisms underpinning estrogen deficiency-related osteoporosis (EDOP) and glucocorticoid-induced osteoporosis (GIOP). The role of estrogen in bone metabolism is critically examined, highlighting its regulatory effects on bone turnover and formation through various signaling pathways. Conversely, this review explores how glucocorticoids disrupt bone homeostasis, focusing on their impact on osteoclast and osteoblast function and the subsequent alteration of bone remodeling processes. The pathogenesis of both conditions is intertwined, with estrogen receptor signaling pathways and the role of inflammatory cytokines being pivotal in driving bone loss. A detailed analysis of pathogenetic and risk factors associated with EDOP and GIOP is presented, including lifestyle and genetic factors contributing to disease progression. Modern therapeutic approaches emphasize pharmacologic, non-pharmacologic, and herbal treatments for managing EDOP and GIOP. In summary, current therapeutic strategies highlight the efficacy and the safety of various interventions. This review concludes with future directions for research, suggesting a need for novel treatment modalities and a deeper understanding of the underlying mechanisms of osteoporosis. By addressing the multifaceted nature of EDOP and GIOP, this work aims to provide insights into developing targeted therapeutic strategies and improving patient outcomes in osteoporosis management.

Nanomaterials-Based Drug Delivery Systems for Therapeutic Applications in Osteoporosis

The etiology of osteoporosis is rooted in the disruption of the intricate equilibrium between bone formation and bone resorption processes. Nevertheless, the conventional anti-osteoporotic medications and hormonal therapeutic regimens currently employed in clinical practice are associated with a multitude of adverse effects, thereby constraining their overall therapeutic efficacy and potential. Recently, nanomaterials have emerged as a promising alternative due to their minimal side effects, efficient drug delivery, and ability to enhance bone formation, aiding in restoring bone balance. This review delves into the fundamental principles of bone remodeling and the bone microenvironment, as well as current clinical treatment approaches for osteoporosis. It subsequently explores the research status of nanomaterial-based drug delivery systems for osteoporosis treatment, encompassing inorganic nanomaterials, organic nanomaterials, cell-mimicking carriers and exosomes mimics and emerging therapies targeting the osteoporosis microenvironment. Finally, the review discusses the potential of nanomedicine in treating osteoporosis and outlines the future trajectory of this burgeoning field. The aim is to provide a comprehensive reference for the application of nanomaterial-based drug delivery strategies in osteoporosis therapy, thereby fostering further advancements and innovations in this critical area of medical research.

In Silico Clinical Trial for Osteoporosis Treatments to Prevent Hip Fractures: Simulation of the Placebo Arm

Osteoporosis represents a major healthcare concern. The development of novel treatments presents challenges due to the limited cost-effectiveness of clinical trials and ethical concerns associated with placebo-controlled trials. Computational models for the design and assessment of biomedical products (In Silico Trials) are emerging as a promising alternative. In this study, a novel In Silico Trial technology (BoneStrength) was applied to replicate the placebo arms of two concluded clinical trials and its accuracy in predicting hip fracture incidence was evaluated. Two virtual cohorts (N = 1238 and 1226, respectively) were generated by sampling a statistical anatomy atlas based on CT scans of proximal femurs. Baseline characteristics were equivalent to those reported for the clinical cohorts. Fall events were sampled from a Poisson distribution. A multiscale stochastic model was implemented to estimate the impact force associated to each fall. Finite Element models were used to predict femur strength. Fracture incidence in 3 years follow-up was computed with a Markov chain approach; a patient was considered fractured if the impact force associated with a fall exceeded femur strength. Ten realizations of the stochastic process were run to reach convergence. Each realization required approximately 2500 FE simulations, solved using High-Performance Computing infrastructures. Predicted number of fractures was 12 ± 2 and 18 ± 4 for the two cohorts, respectively. The predicted incidence range consistently included the reported clinical data, although on average fracture incidence was overestimated. These findings highlight the potential of BoneStrength for future applications in drug development and assessment.

A pre-vertebrate endodermal origin of calcitonin-producing neuroendocrine cells

Vertebrate calcitonin-producing cells (C-cells) are neuroendocrine cells that secrete the small peptide hormone calcitonin in response to elevated blood calcium levels. Whereas mouse C-cells reside within the thyroid gland and derive from pharyngeal endoderm, avian C-cells are located within ultimobranchial glands and have been reported to derive from the neural crest. We use a comparative cell lineage tracing approach in a range of vertebrate model systems to resolve the ancestral embryonic origin of vertebrate C-cells. We find, contrary to previous studies, that chick C-cells derive from pharyngeal endoderm, with neural crest-derived cells instead contributing to connective tissue intimately associated with C-cells in the ultimobranchial gland. This endodermal origin of C-cells is conserved in a ray-finned bony fish (zebrafish) and a cartilaginous fish (the little skate, Leucoraja erinacea). Furthermore, we discover putative C-cell homologs within the endodermally-derived pharyngeal epithelium of the ascidian Ciona intestinalis and the amphioxus Branchiostoma lanceolatum, two invertebrate chordates that lack neural crest cells. Our findings point to a conserved endodermal origin of C-cells across vertebrates and to a pre-vertebrate origin of this cell type along the chordate stem.

Mind the Gap: Unraveling the Intricate Dance Between Alzheimer's Disease and Related Dementias and Bone Health

PURPOSE OF REVIEW

This review examines the linked pathophysiology of Alzheimer's disease/related dementia (AD/ADRD) and bone disorders like osteoporosis. The emphasis is on "inflammaging"-a low-level inflammation common to both, and its implications in an aging population.

RECENT FINDINGS

Aging intensifies both ADRD and bone deterioration. Notably, ADRD patients have a heightened fracture risk, impacting morbidity and mortality, though it is uncertain if fractures worsen ADRD. Therapeutically, agents targeting inflammation pathways, especially Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and TNF-α, appear beneficial for both conditions. Additionally, treatments like Sirtuin 1 (SIRT-1), known for anti-inflammatory and neuroprotective properties, are gaining attention. The interconnectedness of AD/ADRD and bone health necessitates a unified treatment approach. By addressing shared mechanisms, we can potentially transform therapeutic strategies, enriching our understanding and refining care in our aging society. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Pharmacological interventions for bone health in people with epilepsy

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effectiveness of various pharmacological interventions (for treatment and for prevention) for bone health in people with epilepsy.

Insights into the Mechanism of Osteoporosis and the Available Treatment Options

Osteoporosis, one of the most prevalent bone illnesses, majorly affects postmenopausal women and men over 50 years of age. Osteoporosis is associated with an increased susceptibility to fragility fractures and can result in persistent pain and significant impairment in affected individuals. The primary method for diagnosing osteoporosis involves the assessment of bone mineral density (BMD) through the utilisation of dual energy x-ray absorptiometry (DEXA). The integration of a fracture risk assessment algorithm with bone mineral density (BMD) has led to significant progress in the diagnosis of osteoporosis. Given that osteoporosis is a chronic condition and multiple factors play an important role in maintaining bone mass, comprehending its underlying mechanism is crucial for developing more effective pharmaceutical interventions for the disease. The effective management of osteoporosis involves the utilisation of appropriate pharmacological agents in conjunction with suitable dietary interventions and lifestyle modifications. This review provides a comprehensive understanding of the types of osteoporosis and elucidates the currently available pharmacological treatment options and their related mechanism of action and usage.

Using machine learning to identify patients at high risk of developing low bone density or osteoporosis after gastrectomy: a 10-year multicenter retrospective analysis

INTRODUCTION

Osteoporosis that emerges subsequent to gastrectomy poses a significant threat to the long-term health of patients. The primary objective of this investigation was to formulate a machine learning algorithm capable of identifying substantial preoperative, intraoperative, and postoperative risk factors. This algorithm, in turn, would enable the anticipation of osteoporosis occurrence after gastrectomy.

METHODS

This research encompassed a cohort of 1125 patients diagnosed with gastric cancer, including 108 individuals with low bone density or osteoporosis. A total of 40 distinct variables were collected, comprising patient demographics, pertinent medical history, medication records, preoperative examination attributes, surgical procedure specifics, and intraoperative details. Four distinct machine learning algorithms-extreme gradient boosting (XGBoost), random forest (RF), support vector machine (SVM), and k-nearest neighbor algorithm (KNN)-were employed to establish the predictive model. Evaluation of the models involved receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). Shapley additive explanation (SHAP) was employed for visualization and analysis.

RESULTS

Among the four prediction models employed, the XGBoost algorithm demonstrated exceptional performance. The ROC analysis yielded excellent predictive accuracy, showcasing area under the curve (AUC) values of 0.957 and 0.896 for training and validation sets, respectively. The calibration curve further confirmed the robust predictive capacity of the XGBoost model. The DCA demonstrated a notably higher benefit rate for patients undergoing intervention based on the XGBoost model. Moreover, the AUC value of 0.73 for the external validation set indicated favorable extrapolation of the XGBoost prediction model. SHAP analysis outcomes unveiled numerous high-risk factors for osteoporosis development after gastrectomy, including a history of chronic obstructive pulmonary disease (COPD), inflammatory bowel disease (IBD), hypoproteinemia, postoperative neutrophil-to-lymphocyte ratio (NLR) exceeding 3, steroid usage history, advanced age, and absence of calcitonin use.

CONCLUSION

The osteoporosis prediction model derived through the XGBoost machine learning algorithm in this study displays remarkable predictive precision and carries significant clinical applicability.

Yak milk promotes renal calcium reabsorption in mice with osteoporosis via the regulation of TRPV5

The Ca2+-selective epithelial channel TRPV5 plays a significant role in renal calcium reabsorption and improving osteoporosis (OP). In this study, we investigated the mechanisms of yak milk on osteoporosis mice in TRPV5-mediated Ca2+ reabsorption in the kidney. We observed that treatment of OP mice with yak milk reconstructed bone homeostasis demonstrated by increasing the levels of OPG as well as decreasing the levels of TRAP and ALP in serum. Additionally, yak milk reduced the level of parathyroid hormone (PTH) and elevated 1,25-(OH)2D3 and calcitonin (CT), and inhibited the excretion of Ca/Cr and Pi/Cr in OP mice, which explained by regulating hormone levels and thus enhance the renal Ca2+ reabsorption. Further analysis exhibited that yak milk upregulated the expression of TRPV5 protein and mRNA as well as calbindin-D28k in OP mice kidneys. Overall, these outcomes demonstrate that yak milk enhances renal Ca2+ reabsorption through the TRPV5 pathway synergistically with calbindin-D28k, thus ameliorating OP mice. This provides a new perspective for yak milk as a nutritional supplement to prevent osteoporosis.

Molecular and Cellular Mechanisms of Osteoporosis

Osteoporosis is a widespread systemic disease characterized by a decrease in bone mass and an imbalance of the microarchitecture of bone tissue. Experimental and clinical studies devoted to investigating the main pathogenetic mechanisms of osteoporosis revealed the important role of estrogen deficiency, inflammation, oxidative stress, cellular senescence, and epigenetic factors in the development of bone resorption due to osteoclastogenesis, and decreased mineralization of bone tissue and bone formation due to reduced function of osteoblasts caused by apoptosis and age-depended differentiation of osteoblast precursors into adipocytes. The current review was conducted to describe the basic mechanisms of the development of osteoporosis at molecular and cellular levels and to elucidate the most promising therapeutic strategies of pathogenetic therapy of osteoporosis based on articles cited in PubMed up to September 2023.

Smart pills and drug delivery devices enabling next generation oral dosage forms

Oral dosage forms are the preferred solution for systemic treatment and prevention of disease conditions. However, traditional dosage forms face challenges regarding treatment adherence and delivery of biologics. Oral therapies that require frequent administrations face difficulties with patient compliance. In addition, only a few peptide- and protein-based drugs have been commercialized for oral administration so far, presenting a bioavailability that is generally low. Therefore, research and development on novel formulation strategies for oral drug delivery has bloomed massively in the last decade to overcome these challenges. On the one hand, approaches based on lumen-release of drugs such as 3D-printed capsules and prolonged gastric residence dosage forms have been explored to offer personalized medicine to the patient and reduce frequent dosing of small drug compounds that are currently in the market as powdered tablet or capsules. On the other hand, strategies based on mucus interfacing such as gastrointestinal patches, or even epithelium injections have been investigated in order to enhance the permeability of biologic macromolecules, which are mostly commercialized in the form of subcutaneous injections. Despite the fact that these methods are at an early development stage, promising results have been revealed in terms of personalized medicine and improved bioavailability. In this review, we offer a critical overview of novel ingestible millimeter-sized devices and technologies for oral drug delivery that are currently used in the clinic as well as those that could emerge on the market in a not too distant future.

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.

Modulatory Effect of Gut Microbiota on the Gut-Brain, Gut-Bone Axes, and the Impact of Cannabinoids

The gut microbiome is a collection of microorganisms and parasites in the gastrointestinal tract. Many factors can affect this community's composition, such as age, sex, diet, medications, and environmental triggers. The relationship between the human host and the gut microbiota is crucial for the organism's survival and development, whereas the disruption of this relationship can lead to various inflammatory diseases. Cannabidiol (CBD) and tetrahydrocannabinol (THC) are used to treat muscle spasticity associated with multiple sclerosis. It is now clear that these compounds also benefit patients with neuroinflammation. CBD and THC are used in the treatment of inflammation. The gut is a significant source of nutrients, including vitamins B and K, which are gut microbiota products. While these vitamins play a crucial role in brain and bone development and function, the influence of gut microbiota on the gut-brain and gut-bone axes extends further and continues to receive increasing scientific scrutiny. The gut microbiota has been demonstrated to be vital for optimal brain functions and stress suppression. Additionally, several studies have revealed the role of gut microbiota in developing and maintaining skeletal integrity and bone mineral density. It can also influence the development and maintenance of bone matrix. The presence of the gut microbiota can influence the actions of specific T regulatory cells, which can lead to the development of bone formation and proliferation. In addition, its metabolites can prevent bone loss. The gut microbiota can help maintain the bone's equilibrium and prevent the development of metabolic diseases, such as osteoporosis. In this review, the dual functions gut microbiota plays in regulating the gut-bone axis and gut-brain axis and the impact of CBD on these roles are discussed.

Fasudil Ameliorates Osteoporosis Following Myocardial Infarction by Regulating Cardiac Calcitonin Secretion

We hypothesis that Rho kinase inhibitor fasudil ameliorates osteoporosis following myocardial infarction (MI) by regulating cardiac calcitonin secretion. A mice model of MI and cultured neonatal cardiomyocytes exposed to hypoxia and serum deprivation (H/SD), and fibroblasts exposed to TGF-β were used, respectively. Cardiac function in vivo was assessed with echocardiography. Osteoporosis in vivo was assessed with X-ray and micro-CT. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots. In mice post-MI, fasudil ameliorates the microstructure and bone metabolism of the lumbar, improved cardiac function, and attenuated myocardial fibrosis. In vitro, fasudil or αCGRP could effectively inhibit the proliferation of primary fibroblasts treated with TGF-β. Moreover, fasudil ameliorates the cardiac calcitonin secretion induced by MI in vivo or by H/SD in vitro. Our findings suggest that fasudil improved MI-induced osteoporosis by promoting cardiac secreting calcitonin.

A narrative review of the calcitonin peptide family and associated receptors as migraine targets: Calcitonin gene-related peptide and beyond

OBJECTIVE

To summarize the pharmacology of the calcitonin peptide family of receptors and explore their relationship to migraine and current migraine therapies.

BACKGROUND

Therapeutics that dampen calcitonin gene-related peptide (CGRP) signaling are now in clinical use to prevent or treat migraine. However, CGRP belongs to a broader peptide family, including the peptides amylin and adrenomedullin. Receptors for this family are complex, displaying overlapping pharmacologic profiles. Despite the focus on CGRP and the CGRP receptor in migraine research, recent evidence implicates related peptides and receptors in migraine.

METHODS

This narrative review summarizes literature encompassing the current pharmacologic understanding of the calcitonin peptide family, and the evidence that links specific members of this family to migraine and migraine-like behaviors.

RESULTS

Recent work links amylin and adrenomedullin to migraine-like behavior in rodent models and migraine-like attacks in individuals with migraine. We collate novel information that suggests females may be more sensitive to amylin and CGRP in the context of migraine-like behaviors. We report that drugs designed to antagonize the canonical CGRP receptor also antagonize a second CGRP-responsive receptor and speculate as to whether this influences therapeutic efficacy. We also discuss the specificity of current drugs with regards to CGRP isoforms and how this may influence therapeutic profiles. Lastly, we emphasize that receptors related to, but distinct from, the canonical CGRP receptor may represent underappreciated and novel drug targets.

CONCLUSION

Multiple peptides within the calcitonin family have been linked to migraine. The current focus on CGRP and its canonical receptor may be obscuring pathways to further therapeutics. Drug discovery schemes that take a wider view of the receptor family may lead to the development of new anti-migraine drugs with favorable clinical profiles. We also propose that understanding these related peptides and receptors may improve our interpretation regarding the mechanism of action of current drugs.

Cellular Senescence in Bone

Senescence is an irreversible cell-cycle arrest process induced by environmental, genetic, and epigenetic factors. An accumulation of senescent cells in bone results in age-related disorders, and one of the common problems is osteoporosis. Deciphering the basic mechanisms contributing to the chronic ailments of aging may uncover new avenues for targeted treatment. This review focuses on the mechanisms and the most relevant research advancements in skeletal cellular senescence. To identify new options for the treatment or prevention of age-related chronic diseases, researchers have targeted hallmarks of aging, including telomere attrition, genomic instability, cellular senescence, and epigenetic alterations. First, this chapter provides an overview of the fundamentals of bone tissue, the causes of skeletal involution, and the role of cellular senescence in bone and bone diseases such as osteoporosis. Next, this review will discuss the utilization of pharmacological interventions in aging tissues and, more specifically, highlight the role of senescent cells to identify the most effective and safe strategies.

Presence or severity of Hashimoto's thyroiditis does not influence basal calcitonin levels: observations from CROHT biobank

PURPOSE

The influence of Hashimoto's thyroiditis (HT) on calcitonin (Ct) production is unresolved question. The aim of this study was to explore if basal Ct levels are influenced by the presence/severity of HT or correlated with clinical phenotypes of HT patients.

METHODS

We included 467 HT patients and 184 control participants, from Croatian Biobank of HT patients (CROHT), in this retrospective study. Calcitonin levels between HT patients and controls were compared using Mann-Whitney test. Ct levels between two subgroups of HT patients, divided by intake of levothyroxine (LT4) therapy, were additionally tested to take into account the illness severity. Spearman rank correlation test was used to analyze correlations between Ct levels and 14 relevant phenotypes.

RESULTS

We have not detected significant differences in median Ct levels between HT patients and controls (2.2 vs 2.35 pg/mL, respectively, P = 0.717) nor in-between two subgroups of HT patients (P = 0.347). We have not detected statistically significant correlations between Ct levels and clinical phenotypes, although we identified three weak nominal correlations: negative correlation of Ct with TgAb in all HT patients (r = - 0.1, P = 0.04); negative correlation of Ct with age in subgroup of HT patients without LT4 therapy (r = - 0.13, P = 0.04); positive correlation of Ct with BSA in subgroup of HT patients on LT4 therapy (r = 0.16, P = 0.042).

CONCLUSION

Our results suggest that HT patients of all disease stages preserve Ct production as healthy individuals and there is no need for Ct measurements in the absence of a nodule. Additional confirmation and clarification of observed nominal correlations are needed due to potential clinical relevance of TgAb and age-dependent Ct decrease in HT women.

Effects of Teriparatide versus Salmon Calcitonin Therapy for the Treatment of Osteoporosis in Asia: A Meta-analysis of Randomized Controlled Trials

Objective:

The objective of this meta-analysis was to compare the efficacy and safety of teriparatide versus salmon calcitonin for the treatment of osteoporosis in Asian patients and to investigate whether the results of global studies could be applicable to Asian patients.

Methods:

PubMed, OVID, Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE up to December 2018 were searched. Eligible randomized controlled trials (RCTs) that compared teriparatide versus salmon calcitonin in Asian osteoporosis population were included. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for data synthesis, and Cochrane Collaboration software Review Manager 5.3 was used to analyze the pooled data.

Results:

Three RCTs involving 529 patients were included (mean age 68.7 yr; 93.4% females; mean follow-up 6 months); outcome measures included bone mineral density (BMD) of the femoral neck, total hip and lumbar spine; bone markers and adverse events. We found that the period of 6-months of teriparatide treatment was helpful for the improvement of the BMD of lumbar vertebra, however, the improvement of BMD was not significant in the femoral neck and total hip joint. There was a positive correlation between bone-specific alkaline phosphatase (BSAP) and osteocalcin (OCN) and the response of Asian patients to subcutaneous injection of 20 micrograms per day of teriparatide. The proportion of the occurrence of adverse effects was more obvious in the teriparatide group compared with salmon calcitonin, but there was no significant difference.

Conclusion:

Results suggested that the use of teriparatide could improve the lumbar BMD by shortterm (six months) application in Asian osteoporosis patients, which is beneficial to the patients who cannot tolerate adverse events of long-term treatment. The BSAP and OCN bone markers could be useful to monitor the responses of Asian osteoporosis patients to teriparatide treatment. Finally, both of teriparatide and salmon calcitonin were well tolerated by Asian patients.

Osteoporosis in Adult Patients with Intellectual and Developmental Disabilities: Special Considerations for Diagnosis, Prevention, and Management

As medical care progresses, patients with intellectual and developmental disabilities are living longer and beginning to experience diseases that commonly afflict the aging population, such as osteoporosis. Osteoporosis and resultant fractures increase disability and threaten the independence of this vulnerable population. In addition, the diagnosis, prevention, and management of osteoporosis present unique challenges in these patients. Critical preventive targets include exercise modification, fall prevention, and monitoring for nutrient deficiencies. Commonly used in diagnosis and treatment monitoring, dual-energy x-ray absorptiometry (DXA) scan of the hip and spine may not be feasible, whereas peripheral DXA or computed tomography may be more accessible for patients with physical disabilities. Pharmacological treatment should be tailored to the individual patient, considering factors such as adherence and comorbidities. Finally, bone turnover markers are a noninvasive, cost-effective option for monitoring treatment response in patients who cannot undergo DXA.

miR-21-5p targets SKP2 to reduce osteoclastogenesis in a mouse model of osteoporosis

Osteoporosis results from an imbalance between bone formation and bone resorption. Traditional drugs for treating osteoporosis are associated with serious side effects, and thus, new treatment methods are required. This study investigated the role of differentially expressed microRNAs during osteoclast differentiation and osteoclast activity during osteoarthritis as well as the associated underlying mechanisms. We used a microarray to screen microRNAs that decreased in the process of osteoclast differentiation and verified miR-21-5p to decrease significantly using RT-qPCR. In follow-up experiments, we found that miR-21-5p targets SKP2 to regulate osteoclast differentiation. In vivo, ovariectomized mice were used to simulate perimenopausal osteoporosis induced by estrogen deficiency, and miR-21-5p treatment inhibited bone resorption and maintained bone cortex and trabecular structure. These results suggest that miR-21-5p is a new therapeutic target for osteoporosis.

Molecular Signaling Pathways and Essential Metabolic Elements in Bone Remodeling: An Implication of Therapeutic Targets for Bone Diseases

Bone is one of the dynamic tissues in the human body that undergoes continuous remodelling through subsequent actions of bone cells, osteoclasts, and osteoblasts. Several signal transduction pathways are involved in the transition of mesenchymal stem cells into osteoblasts. These primarily include Runx2, ATF4, Wnt signaling and sympathetic signalling. The differentiation of osteoclasts is controlled by M-CSF, RANKL, and costimulatory signalling. It is well known that bone remodelling is regulated through receptor activator of nuclear factor-kappa B ligand followed by binding to RANK, which eventually induces the differentiation of osteoclasts. The resorbing osteoclasts secrete TRAP, cathepsin K, MMP-9 and gelatinase to digest the proteinaceous matrix of type I collagen and form a saucer-shaped lacuna along with resorption tunnels in the trabecular bone. Osteoblasts secrete a soluble decoy receptor, osteoprotegerin that prevents the binding of RANK/RANKL and thus moderating osteoclastogenesis. Moreover, bone homeostasis is also regulated by several growth factors like, cytokines, calciotropic hormones, parathyroid hormone and sex steroids. The current review presents a correlation of the probable molecular targets underlying the regulation of bone mass and the role of essential metabolic elements in bone remodelling. Targeting these signaling pathways may help to design newer therapies for treating bone diseases.

The effects of calcitonin on post-orthodontic relapse in rats

Objectives

To determine the effects of systematic calcitonin administration on post‐orthodontic relapse in rat model.

Material and methods

This experimental animal model involved 36 male Wister rats. The maxillary right first molars were moved mesially, using a modified orthodontic appliance delivered 50 gm, for 14 days, retained for 4 days and left to relapse for 10 days. The study group was divided into three subgroups in which a single injection of calcitonin (20 IU/Kg), three injections of calcitonin (20 IU/Kg), each every other day, and normal saline were administered subcutaneously after orthodontic tooth movement has finished. The relapse ratio, histomorphometric analysis including osteoblasts, osteoclasts numbers and bone area and immunohistochemical analysis including the expression of receptor activator of nuclear factor kappa Β (RANK), receptor activator of nuclear factor kappa Β ligand (RANKL) and osteoprotegerin (OPG) were measured and assessed.

Results

The relapse ratio was significantly reduced in the three‐dose calcitonin group (28%) compared to the single dose calcitonin group (34%) and the control group (46%). This was accompanied by a nonsignificant increase in osteoblasts number and bone area in three‐dose calcitonin group and a nonsignificant reduction in osteoclast number. However, the immune histochemical expression of RANK, RANKL and OPG did not show statistically significant difference at the end of relapse period.

Conclusions

Systemic administration of three doses of calcitonin may minimize the relapse ratio in experimentally moved rat molars.

Effects of bisphosphonates on osteoporosis: Focus on zoledronate

Osteoporosis is a bone disease that mainly affects older people and postmenopausal women. Lack of proper treatment for this disease gives rise to many problems in patients and occasionally leads to death. Many drugs have been utilized to treat osteoporosis but the most effective one is the bisphosphonates (BPs) family. This family has several positive effects on bone tissue, including promoting bone healing, enhancing bone mineral density, reducing bone resorption, preventing pathologic fractures, suppressing bone turnover, and modulating bone remodeling. On the other hand, there have also been inconclusive reports that BPs might have a desirable or even adverse impact on osteoporotic patients. Therefore, we set out to examine the positive and negative effects of this family, with a focus on the most potent one that is zoledronate (Zol), in clinical usage. Zoledronate is an amino-BPs and nitrogen-containing drug which is the most powerful BPs on osteoporosis treatment or prevention. Many studies showed its effectiveness in the treatment of osteoporosis and bone healing. As Zol enjoys a considerable potential in treating and preventing osteoporosis, it can be used as one of the effective treatments in this field.

Molecular Mechanisms and Emerging Therapeutics for Osteoporosis

Osteoporosis is the most common chronic metabolic bone disease. It has been estimated that more than 10 million people in the United States and 200 million men and women worldwide have osteoporosis. Given that the aging population is rapidly increasing in many countries, osteoporosis could become a global challenge with an impact on the quality of life of the affected individuals. Osteoporosis can be defined as a condition characterized by low bone density and increased risk of fractures due to the deterioration of the bone architecture. Thus, the major goal of treatment is to reduce the risk for fractures. There are several treatment options, mostly medications that can control disease progression in risk groups, such as postmenopausal women and elderly men. Recent studies on the basic molecular mechanisms and clinical implications of osteoporosis have identified novel therapeutic targets. Emerging therapies targeting novel disease mechanisms could provide powerful approaches for osteoporosis management in the future. Here, we review the etiology of osteoporosis and the molecular mechanism of bone remodeling, present current pharmacological options, and discuss emerging therapies targeting novel mechanisms, investigational treatments, and new promising therapeutic approaches.

Down-regulation of LECT2 promotes osteogenic differentiation of MSCs via activating Wnt/β-catenin pathway

Osteoporosis is a result of the imbalance between osteoblasts and osteoclasts quantities, which is closely correlated with osteogenic differentiation (OD). Leucocyte cell-derived chemotaxin 2 (LECT2) has been reported as a regulatory factor in some chronic diseases such as hepatitis through mediating downstream target gene β-catenin. Additionally, Wnt/β-catenin is also the crucial modulatory signal pathway in OD. Mesenchymal stem cells (MSC) is a kind of mesodermal stem cells; its differentiation direction is discovered affected by Wnt/β-catenin. However, the function of LECT2 in osteoporosis still remains exploration, which encourages us to lucubrate its functional effect in regulating the OD of MSCs. In this study, we found that LECT2 was expressed at low level in MSCs with osteogenic differentiation, and knockdown of LECT2 would activate Wnt/β-catenin pathway and therefore promoting OD in MSCs. It is the first time to report that LECT2 participates in regulating OD via mediating Wnt/β-catenin. Our discovery would affirmatively help provide a novel strategy for the diagnosis and therapy methods for osteoporosis.

Clinical effect of intramuscular calcitonin compared with oral celecoxib in the treatment of knee bone marrow lesions: a retrospective study

BACKGROUND

Bone marrow lesions (BMLs) are a common finding in patients with osteoarthritis (OA), which are predictors of progression and pain related to cartilage damage in OA. The objective of the present research was to compare the short-term clinical effect of intramuscular calcitonin and oral celecoxib in treating knee BMLs.

PATIENTS AND METHODS

Between January 2016 and December 2018, the medical records of patients with knee BMLs treated by intramuscular calcitonin or oral celecoxib were reviewed. Visual analog scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were used to assess knee pain and function, respectively. BMLs were assessed by MRI scans and were scored by the modified Whole-Organ MRI Score (WORMS). The safety of these two medications was also evaluated.

RESULTS

A total of 123 eligible patients who received calcitonin treatment (n = 66) or celecoxib treatment (n = 57) were included. All patients were followed up clinically and radiographically for 3 months. The VAS and WOMAC scores were lower statistically in calcitonin group than celecoxib group at 4-week and 3-month follow-up. For BMLs, the WORMS scores in the calcitonin group were significantly lower than the celecoxib group. Besides, statistically higher MRI improvement rates were found in the calcitonin group compared with the celecoxib group at 4-week follow-up (21.21% vs. 7.01%; P = 0.039) and 3-month follow-up (37.88% vs. 15.79%; P = 0.006).

CONCLUSION

Intramuscular calcitonin 50 IU once daily demonstrated a better short-term effect for knee BML patients compared with oral celecoxib 200 mg twice per day.

Molecular-Based Treatment Strategies for Osteoporosis: A Literature Review

Osteoporosis is an unavoidable public health problem in an aging or aged society. Anti-resorptive agents (calcitonin, estrogen, and selective estrogen-receptor modulators, bisphosphonates, anti-receptor activator of nuclear factor κB ligand antibody along with calcium and vitamin D supplementations) and anabolic agents (parathyroid hormone and related peptide analogs, sclerostin inhibitors) have major roles in current treatment regimens and are used alone or in combination based on the pathological condition. Recent advancements in the molecular understanding of bone metabolism and in bioengineering will open the door to future treatment paradigms for osteoporosis, including antibody agents, stem cells, and gene therapies. This review provides an overview of the molecular mechanisms, clinical evidence, and potential adverse effects of drugs that are currently used or under development for the treatment of osteoporosis to aid clinicians in deciding how to select the best treatment option.

An amylin analogue attenuates alcohol-related behaviours in various animal models of alcohol use disorder

Recent findings have identified salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, as a potential regulator of alcohol-induced activation of the mesolimbic dopamine system and alcohol consumption. Providing that the role of amylin signalling in alcohol-related behaviours remains unknown, the present experiments investigate the effect of sCT on these behaviours and the mechanisms involved. We showed that repeated sCT administration decreased alcohol and food intake in outbred rats. Moreover, single administration of the potent amylin receptor antagonist, AC187, increased short-term alcohol intake in outbred alcohol-consuming rats, but did not affect food intake. Acute administration of sCT prevented relapse-like drinking in the "alcohol deprivation effect" model in outbred alcohol-experienced rats. Additionally, acute sCT administration reduced operant oral alcohol self-administration (under the fixed ratio 4 schedule of reinforcement) in selectively bred Sardinian alcohol-preferring rats, while it did not alter operant self-administration (under the progressive ratio schedule of reinforcement) of a highly palatable chocolate-flavoured beverage in outbred rats. Lastly, we identified differential amylin receptor expression in high compared to low alcohol-consuming rats, as reflected by decreased calcitonin receptor and increased receptor activity modifying protein 1 expression in the nucleus accumbens (NAc) of high consumers. Collectively, our data suggest that amylin signalling, especially in the NAc, may contribute to reduction of various alcohol-related behaviours.

Activation of amylin receptors attenuates alcohol-mediated behaviours in rodents

Alcohol expresses its reinforcing properties by activating areas of the mesolimbic dopamine system, which consists of dopaminergic neurons projecting from the ventral tegmental area to the nucleus accumbens. The findings that reward induced by food and addictive drugs involve common mechanisms raise the possibility that gut-brain hormones, which control appetite, such as amylin, could be involved in reward regulation. Amylin decreases food intake, and despite its implication in the regulation of natural rewards, tenuous evidence support amylinergic mediation of artificial rewards, such as alcohol. Therefore, the present experiments were designed to investigate the effect of salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, on various alcohol-related behaviours in rodents. We showed that acute sCT administration attenuated the established effects of alcohol on the mesolimbic dopamine system, particularly alcohol-induced locomotor stimulation and accumbal dopamine release. Using the conditioned place preference model, we demonstrated that repeated sCT administration prevented the expression of alcohol's rewarding properties and that acute sCT administration blocked the reward-dependent memory consolidation. In addition, sCT pre-treatment attenuated alcohol intake in low alcohol-consuming rats, with a more evident decrease in high alcohol consumers in the intermittent alcohol access model. Lastly, sCT did not alter peanut butter intake, blood alcohol concentration and plasma corticosterone levels in mice. Taken together, the present data support that amylin signalling is involved in the expression of alcohol reinforcement and that amylin receptor agonists could be considered for the treatment of alcohol use disorder in humans.

Clinical efficacy of calcitonin compared to diclofenac sodium in chronic nonspecific low back pain with type I Modic changes: a retrospective study

Background

The objective of this study was to compare the efficacy of calcitonin with diclofenac sodium in the treatment of patients with nonspecific low back pain (LBP) and type I Modic changes (MC1).

Patients and methods

The study was a retrospective observational study with 109 patients who had nonspecific LBP and MC1 that appeared as bone marrow lesions on magnetic resonance imaging (MRI). Between October 2013 and March 2016, 62 patients were injected intramuscularly with calcitonin 50 IU once daily and 47 patients were treated with diclofenac 75 mg once per day for 4 weeks for the treatment of LBP associated with MC1 on MRI. Visual analog scale (VAS) (0–10) and Oswestry Disability Index (ODI) (0–100) questionnaires were acquired from clinical records to evaluate LBP perception and degree of disability. Imaging data were also collected before and after treatment.

Results

Significant improvements were found in VAS and ODI at posttreatment compared with baseline in both groups (P < 0.05). Meanwhile, there was a significant difference between calcitonin group and diclofenac group at both 4 weeks and 3 months of follow-up (4 weeks: VAS 4.46 ± 1.58 vs 5.08 ± 1.50, ODI 20.32 ± 9.64 vs 24.35 ± 7.95; 3 months: VAS 3.70 ± 1.74 vs 4.51 ± 1.67, ODI 16.67 ± 9.04 vs 21.18 ± 9.56; P < 0.05 for all). Moreover, the proportion of patients with a significant change in LBP scales was higher in the calcitonin group (4 weeks: VAS 50.00% vs 23.40%, ODI 54.83% vs 25.53%; 3 months: VAS 58.06% vs 38.29%, ODI 59.67% vs 38.29%; P < 0.05 for all). According to MRI, 43.54% patients in the calcitonin group showed improvement compared with 21.27% patients in the diclofenac group (P < 0.05).

Conclusion

There was greater short-term efficacy of calcitonin compared with diclofenac in patients with LBP and MC1 on MRI.

Enhanced osseointegration of titanium implants in a rat model of osteoporosis using multilayer bone mesenchymal stem cell sheets

The present study aimed to investigate whether bone marrow-derived mesenchymal stem cell (BMSC) sheets combined with titanium implants enhanced implant osseointegration in an ovariectomized (OVX) rat model of osteoporosis. Sprague-Dawley rats were randomly assigned into a test group and control group. Allogenic BMSCs were collected from the rats, cultured and stored via cryopreservation. At 6 months post-ovariectomy, establishment of the OVX model was confirmed by micro-computed tomography (CT) measurements. BMSC sheets were subsequently layered and wrapped over titanium implants for implantation. Unmodified implants served as the control. At 8 weeks post-implantation, samples were observed by micro-CT reconstruction and histomorphometric evaluation. Micro-CT reconstruction identified a marked improvement in the surrounding bone volume following treatment, with data analyses indicating a significant increase in bone volume in the BMSC-implant group compared with the control implant group (P<0.05). In addition, histological staining identified new bone formation and an increased rate of bone-implant contact surrounding the BMSC-implant constructs. These results indicate that the use of BMSC sheets as a novel tissue engineering approach improves the osseointegration of titanium implants in an osteoporosis model. This method may expand the operative indications in patients with osteoporosis and improve the success rate of clinical dental implant treatments.

Efficacy of statins for osteoporosis: a systematic review and meta-analysis

Our meta-analysis assessed the efficacy of statins on the risk of fracture, bone mineral density (BMD), and the markers of bone metabolism by collecting data from 33 clinical trials. We found that statin treatment was associated with bone metabolism. And statins seemed to be more effective on male patients with osteoporosis. The efficacy of statins for the treatment of osteoporosis has been controversial in previous studies and meta-analyses. Our meta-analysis was conducted to examine in detail the efficacy of statins on osteoporosis. We searched PubMed, Embase, and the Cochrane Library databases for clinical trials from inception to May 2016. We included studies that described the effect of statins on the risk of fracture, BMD, or bone turnover markers. Moreover, we also conducted subgroup analyses according to the skeleton site, patient gender, and length of follow-up. A total of 33 studies which included 23 observational studies (16 cohort studies and 7 case-control studies) and 10 randomized controlled trials (RCTs) were evaluated. These 33 studies included 314,473 patients in statin group and 1,349,192 patients in control group. Statins decreased the risk of overall fractures (OR = 0.81, 95% CI 0.73-0.89) and hip fractures (OR = 0.75, 95% CI 0.60-0.92). Furthermore, the use of statins was associated with increased BMD at the total hip (standardized mean difference (SMD) = 0.18, 95% CI 0.00-0.36) and lumbar spine (SMD = 0.20, 95% CI 0.07-0.32) and improved the bone formation marker, osteocalcin (OC) (SMD = 0.21, 95% CI 0.00-0.42). However, there was no positive effect on vertebral fractures, upper extremity fractures, BMD at the femoral neck, bone-specific alkaline phosphatase (BALP), and serum C-terminal peptide of type I collagen (S-CTX). Also, compared with male subgroups, the effect on female subgroups was only slightly positive or of no statistical significance. Our meta-analysis indicates that statin treatment may be associated with a decreased risk of overall fractures and hip fractures, an increased BMD at the total hip, BMD at the lumbar spine, and OC. Moreover, our results also show that statin treatment may have a greater effect on male patients than on female patients.

Treatments for post-menopausal osteoporotic women, what's new? How can we manage long-term treatment?

Since the mid-1980s, postmenopausal osteoporosis (PMO) has been considered a serious public health concern because of the associated fractures. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass have been and are being developed continuously. Most current agents inhibit bone loss by reducing bone resorption, but emerging therapies may increase bone mass by stimulating bone formation. Furthermore, nowadays, the most representative pharmaceuticals have been prescribed long enough to include the reporting of some adverse effects. This review discusses osteoporotic drugs that are approved or are under investigation for the treatment of post-menopausal women (PMW), paying particular attention to long-term treatments.

Current Clinical Practice Scenario of Osteoporosis Management in India

BACKGROUND

Various osteoporosis guidelines are available for practice.

AIM

To understand the current clinical practice scenario from the perspective of Indian orthopaedicians, especially about the epidemiology, clinical manifestations, approach to diagnosis and management and patient compliance patterns to long term treatment.

MATERIALS AND METHODS

A pre-validated structured questionnaire containing questions (mostly objective, some open-ended) catering to various objectives of the study was circulated amongst orthopaedic surgeons across India by means of post/courier, after giving a brief overview of the study telephonically. Data was extracted from the completed questionnaires, and analysed using Microsoft Excel software.

RESULTS

The questionnaire was filled by a total of 84 orthopaedicians throughout India. The prevalence of osteoporosis in India according to the orthopaedic surgeons was 38.4% and there was a female preponderance. Most of the respondents felt out of every 100 osteoporosis patients in India, less than 20 patients are actually diagnosed and treated for osteoporosis. The most common initial presenting feature of established osteoporosis cases was general symptoms. Most respondents preferred Dual-energy X-ray absorptiometry (DEXA) as the initial investigation for the diagnosis of osteoporosis in a patient presenting with typical features. While most respondents preferred once-a-month oral over intravenous (IV) bisphosphonates, they agreed that IV administration had advantages such as lower gastrointestinal side effects and improved compliance. The average duration of therapy of oral bisphosphonates was the longest (27.04 months) among the other anti- osteoporosis therapies that they used. On an average, the patient compliance rate in osteoporosis management was around 64%. IV Zoledronic acid (ZA) and intranasal calcitonin were infrequently used than other anti- osteoporosis therapies. While concerns about cost and availability deterred more frequent usage, there was an agreement that if used regularly these two agents may improve compliance rates among patients.

CONCLUSION

Current clinical practice scenario of osteoporosis management in India largely adheres to various clinical practice guidelines for osteoporosis. Side effects and lengthy duration of therapy with bisphosphonates seem to be the main factors leading to a low patient compliance. Widespread popularization of once-yearly Zoledronic acid and intranasal calcitonin spray may improve patient compliance and reduce side effect incidence.

Insights from the Den: How Hibernating Bears May Help Us Understand and Treat Human Disease

Hibernating brown bears (Ursus arctos) and black bears (Ursus americanus) spend half of the year in a physically inactive state inside their winter dens without food intake and defecating and no or little urination. Under similar extreme conditions, humans would suffer from loss of lean body mass, heart failure, thrombosis, azotemia, osteoporosis, and more. However, bears exit the den in the spring strong without organ injuries. Translational animal models are used in human medicine but traditional experimental animals have several shortcomings; thus, we believe that it is time to systematically explore new models. In this review paper, we describe physiological adaptations of hibernating bears and how similar adaptations in humans could theoretically alleviate medical conditions. The bear has solved most of the health challenges faced by humans, including heart and kidney disease, atherosclerosis and thrombosis, and muscle wasting and osteoporosis. Understanding and applying this library of information could lead to a number of major discoveries that could have implications for the understanding and treatment of human disease.

Investigation of Bone Health Subsequent to Vitamin D Supplementation in Children Following Burn Injury

BACKGROUND

The effect of supplemental vitamin D on fracture occurrence following burn injuries is unclear. The objective of this study was to evaluate postintervention incidence of fractures in children during the rehabilitative phase postburn (PB) following participation in a randomized clinical trial of vitamin D supplementation.

MATERIALS AND METHODS

Follow-up for fracture evaluation was obtained in 39 of 50 patients randomized to daily enteral vitamin D2, D3, or placebo throughout the acute burn course. Serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, D2, D3, calcitonin, and bone alkaline phosphatase (BAP) measurements were obtained PB day 7, midpoint, discharge, and 1-year PB. Urinary calcium was obtained PB day 7 and midpoint. Dual-energy x-ray absorptiometry (DXA) was performed at discharge and 1-year PB.

RESULTS

Fractures were reported in 6 of 39 respondents. Four fractures occurred in the placebo group, 2 in the D2 group, and none in the D3 group. Serum vitamin D, calcitonin, BAP, and urinary calcium were similar between fracture groups. The group with fracture morbidity had larger burn size (83.8% ± 4.9% vs 53.0% ± 2.9%, P < .0001), greater full-thickness burn (69.7% ± 9.4% vs 39.4% ± 4.1%, P = .02), and increased incidence of inhalation injury (33% vs 6%, P = .04). Decreased bone mineral density z score was noted at discharge in the placebo fracture compared with no-fracture group (P < .05).

CONCLUSION

This preliminary report suggests there may be benefit of vitamin D3 in reducing postdischarge fracture risk. Results reaffirm the importance of monitoring bone health in pediatric patients postburn.

Osteoporosis prevention, screening, and treatment: a review

Osteoporosis, defined as low bone mass leading to increased fracture risk, is a major health problem that affects approximately 10 million Americans. The aging U.S. population is predicted to contribute to as much as a 50% increase in prevalence by 2025. Although common, osteoporosis can be clinically silent, and without prevention and screening, the costs of osteoporotic fracture-related morbidity and mortality will burden the U.S. healthcare system. This is a particularly relevant concern in the context of diminishing health care resources. Dual-energy X-ray absorptiometry is the most widely used, validated technique for measuring bone mineral density (BMD) and diagnosing osteoporosis. Cost-effectiveness analyses support early detection and treatment of high-risk patients with antiresorptive medications such as bisphosphonates. Moreover, optimization of bone health throughout life can help prevent osteoporosis. Current guidelines recommend screening women by age 65 years, but because no guidelines for screening intervals exist, decisions are made on the basis of clinical judgment alone. Although the recent literature provides some guidance, this review further explores current recommendations in light of newer evidence to provide more clarity on prevention, screening, and management strategies for patients with osteoporosis in the primary care setting.

Permeation of insulin, calcitonin and exenatide across Caco-2 monolayers: measurement using a rapid, 3-day system

Objectives

Caco-2 monolayers are one of the most widely used in vitro models for prediction of intestinal permeability of therapeutic molecules. However, the conventional Caco-2 monolayer model has several drawbacks including labor-intensive culture process, unphysiological growth conditions, lack of reproducibility and limited throughput. Here, we report on the use of 3-day Caco-2 monolayers for assessing permeability of polypeptide drugs.

Methods

The 3-day monolayers were grown in a commercially available transwell set-up, which facilitates rapid development of the Caco-2 monolayers in an intestinal epithelial differentiation mimicking environment. This set-up included use of serum-free medium of defined composition with supplements such as butyric acid, hormones, growth factors, and other metabolites, reported to regulate the differentiation of intestinal epithelial cells in vivo. We measured permeability of 3 different therapeutic polypeptides; insulin, calcitonin, and exenatide across the monolayer.

Results

Preliminary validation of the monolayer was carried out by confirming dose-dependent permeation of FITC-insulin and sulforhodamine-B. Transport of insulin, calcitonin, and exenatide measured at different loading concentrations suggests that the permeability values obtained with 3-day cultures resemble more closely the values obtained with ex vivo models compared to permeability values obtained with conventional 21-day cultures.

Conclusions

Short-term 3-day Caco-2 monolayers provide new opportunities for developing reproducible and high-throughput models for screening of therapeutic macromolecules for oral absorption.

Recommendations on the management of fragility fracture risk in women younger than 70 years

The risk for fragility fracture represents a problem of enormous magnitude. It is estimated that only a small fraction of women with this risk take the benefit of preventive measures. The relationship between estrogen and bone mass is well known as they are the other factors related to the risk for fracture. There are precise diagnostic methods, including a tool to diagnose the risk for fracture. Yet there continues to be an under-diagnosis, with the unrecoverable delay in instituting preventive measures. Women under the age of 70 years, being much more numerous than those older, and having risk factors, are a group in which it is essential to avoid that first fragility fracture. Today it is usual not to differentiate between the treatment and the prevention of osteoporosis since the common aim is to prevent fragility fractures. Included in this are women with osteoporosis or with low bone mass and increased risk for fracture, for whom risk factors play a primary role. There is clearly controversy over the type of treatment and its duration, especially given the possible adverse effects of long-term use. This justifies the concept of sequential treatment, even more so in women under the age of 70, since they presumably will need treatment for many years. Bone metabolism is age-dependent. In postmenopausal women under 70 years of age, the increase in bone resorption is clearly predominant, related to a sharp drop in estrogens. Thus a logical treatment is the prevention of fragility fractures by hormone replacement therapy (HRT) and, in asymptomatic women, selective estradiol receptor modulators (SERMs). Afterwards, there is a period of greater resorption, albeit less intense but continuous, when one could utilise anti-resorptive treatments such as bisphosphonates or denosumab or a dual agent like strontium ranelate. Bone formation treatment, such as parathyroid hormone (PTH), in women under 70 years will be uncommon. That is because it should be used in cases where the formation is greatly diminished and there is a high risk for fracture, something found in much older women.

Quality analysis of salmon calcitonin in a polymeric bioadhesive pharmaceutical formulation: sample preparation optimization by DOE

A sensitive and selective HPLC method for the assay and degradation of salmon calcitonin, a 32-amino acid peptide drug, formulated at low concentrations (400 ppm m/m) in a bioadhesive nasal powder containing polymers, was developed and validated. The sample preparation step was optimized using Plackett-Burman and Onion experimental designs. The response functions evaluated were calcitonin recovery and analytical stability. The best results were obtained by treating the sample with 0.45% (v/v) trifluoroacetic acid at 60 degrees C for 40 min. These extraction conditions did not yield any observable degradation, while a maximum recovery for salmon calcitonin of 99.6% was obtained. The HPLC-UV/MS methods used a reversed-phase C(18) Vydac Everest column, with a gradient system based on aqueous acid and acetonitrile. UV detection, using trifluoroacetic acid in the mobile phase, was used for the assay of calcitonin and related degradants. Electrospray ionization (ESI) ion trap mass spectrometry, using formic acid in the mobile phase, was implemented for the confirmatory identification of degradation products. Validation results showed that the methodology was fit for the intended use, with accuracy of 97.4+/-4.3% for the assay and detection limits for degradants ranging between 0.5 and 2.4%. Pilot stability tests of the bioadhesive powder under different storage conditions showed a temperature-dependent decrease in salmon calcitonin assay value, with no equivalent increase in degradation products, explained by the chemical interaction between salmon calcitonin and the carbomer polymer.

Analysis of correlation between blood biochemical indicators and bone mineral density of post-menopausal women

Osteoporosis is a degenerative disease of the skeletal system, and its major complication is fracture that severely influences the living quality of the middle-aged and the aged. The purpose of this study was to investigate the significance of sex hormones and some biochemical indicators related to bone metabolism in the genesis and development of osteoporosis. The plasma samples were collected from 244 post-menopausal women of Xi'an urban area, and their plasma contents of testosterone, estradiol, calcitonin, osteocalcin and N-terminal propeptide of type I procollagen were detected by ELISA. The activity of tartrate-resistant acid phosphatase was determined by spectrophotometric method, and the content of nitric oxide was measured by Griess method. Bone mineral density (BMD) in lumbar vertebrae (L1-L4) and hips was measured by QDR-2000 dual energy X-ray absorptiometry. The concentrations of the biochemical indicators were compared among the three groups (normal bone mass group, osteopenia group and osteoporosis group), and Pearson correlation analysis was used to verify the correlations between the indicators and BMD. The comparison results of blood biochemical indicators of BMD-based groups showed that the plasma contents of estradiol (P = 0.006), testosterone (P = 0.038) and calcitonin (P = 0.042) decreased more significantly in the osteoporosis group, but the content of osteocalcin (P = 0.008) increased significantly in osteoporosis group than those in the other groups. The correlation analysis between BMD of different parts and the blood biochemical indicators showed that there was a significant positive correlation between estradiol and the BMD of lumber vertebra (r = 0.200, P = 0.002), femoral neck (r = 0.160, P = 0.013), and great trochanter (r = 0.204, P = 0.001). Significant positive correlations between calcitonin and BMD of lumber vertebra (r = 0.166, P = 0.018) and femoral great trochanter (r = 0.152, P = 0.041), and between testosterone and BMD of femoral great trochanter (r = 0.158, P = 0.014) were also observed. In addition, there existed significant negative correlations between osteocalcin and BMD of lumber vertebra (r = -0.220, P = 0.001), femoral neck (r = -0.259, P < 0.000), and great trochanter (r = -0.221, P = 0.001), and between the activity of tartrate-resistant acid phosphatase and BMD of femoral great trochanter (r = -0.135, P = 0.037). The partial correlation analysis also showed that there were significant correlations between estradiol (r = 0.160, P = 0.014), calcitonin (r = 0.240, P = 0.013), osteocalcin (r = -0.226, P = 0.023) and BMD when the influence of age was excluded. The Pearson correlation analysis of biochemical indicators showed there were positive correlations between the contents of testosterone and calcitonin, testosterone and osteocalcin, calcitonin and osteocalcin, calcitonin and PINP, calcitonin and NO, osteocalcin and NO, and PINP and NO, but negative correlations between the contents of testosterone and PINP, estradiol and calcitonin, estradiol and osteocalcin, and estradiol and NO. The blood contents of sex hormones and calcitonin significantly influence BMD and osteoporosis development, and the increase of osteocalcin contents could be used as a biomarker to indicate the degree of osteoporosis in post-menopausal women.

The role of intranasal estradiol spray in the management of moderate to severe vasomotor symptoms in menopausal women

Hormone therapy (HT) is the most effective treatment at present available for climacteric symptoms. As harmful effects were highlighted in recent randomized clinical trials, the risk-benefit ratio does not favor the use of HT for prevention of cardiovascular diseases and bone fractures in postmenopausal women. Nevertheless, experimental and clinical trials suggest that adverse effects of HT basically depend on the estrogen and progestin formulation, dosage, route of administration, patient's age, associated diseases, and duration of treatment. All estrogen formulations and routes of administration have comparable beneficial effects on vasomotor and urogenital symptoms and on bone structure. But adverse effects may differ. Thus, cardiovascular and invasive breast cancer risks are higher with oral estrogen than with transdermal estradiol. However, transdermal estradiol is not free of inconveniences such as differences among individuals in absorption rates, loss of patches due to poor adhesion, and skin irritation. HT requires careful adjustment to each individual patient and continuous monitoring of clinical evolution. In the future, this adjustment and maybe the use of alternative routes such as intranasal could benefit from genetic screening to maximize in each individual the ratio between positive and adverse effects of HT.