Hormone replacement therapy, selective estrogen receptor modulators, and tissue-specific compounds: cardiovascular effects and clinical implications

Biologics: Teriparatide and Newer Anabolics

The landscape of osteoporosis management has evolved significantly over the years, witnessing a paradigm shift from conventional therapies to the emergence of biologic agents. This chapter delves into the intricate mechanisms, potential applications, and future directions of biologic interventions in osteoporosis care. Biologic agents, with their targeted approach to bone health, have revolutionized the field by offering precision-driven strategies that address the underlying mechanisms of bone fragility. This chapter explores the mechanisms of action of various biologics, including Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL) inhibitors, monoclonal antibodies targeting sclerostin, parathyroid hormone (PTH) analogues, and cathepsin K inhibitors. It discusses their potential benefits, limitations, and safety considerations, while shedding light on the promise of combination therapies that merge biologic agents with traditional approaches. Furthermore, the chapter delves into the potential applications of biologic agents in specific patient populations, the role of biomarkers in predicting treatment responses, and the influence of emerging biological targets. It also explores the advancements in novel targets and drug delivery systems that aim to enhance treatment convenience and effectiveness. By tailoring treatments based on patient characteristics and exploring novel therapeutic targets, the chapter envisions a future of precision medicine in osteoporosis care. As research continues to evolve, the chapter anticipates a transformative impact on bone health outcomes, fracture prevention, and overall quality of life for individuals at risk of osteoporosis-related fractures. Through comprehensive insights into the mechanisms, applications, and future directions of biologic agents, this chapter offers a holistic perspective on the evolving landscape of osteoporosis management.

Conjugated estrogens for the treatment of menopausal symptoms: a review of safety data

INTRODUCTION

Conjugated equine estrogens (CEE) are widely used for the treatment of menopausal symptoms, such as vasomotor symptoms and vulvovaginal atrophy, and for the prevention of bone loss, in postmenopausal women. The safety profile of CEE has been extensively published over the past 20 years.

AREAS COVERED

Data from randomized controlled trials and from observational studies on the effects of CEE on the risk of breast cancer, endometrial cancer or hyperplasia, other cancers, cardiovascular outcomes, and cognitive function are reviewed. When used alone, CEE are not associated with an increased risk of breast cancer and may be associated with reduced mortality. The risk of cardiovascular events with CEE may be reduced in women who are more recently postmenopausal.

EXPERT OPINION

Numerous clinical studies have evaluated the safety of CEE. The data reviewed in this article describe the breast, endometrial, and cardiovascular safety of unopposed CEE. International recommendations describe CEE as the menopausal symptom treatment of choice, particularly in young or recently postmenopausal hysterectomized women.

Glyceollins, one of the phytoalexins derived from soybeans under fungal stress, enhance insulin sensitivity and exert insulinotropic actions

Glyceollins are a category of phytoalexins that are produced by soybeans under fungal stress, but their effects on glucose homeostasis remain unknown. We hypothesized that glyceollins play an important role in glucose homeostasis by regulating glucose utilization in adipocytes and improving beta-cell function and survival. Glyceollins improved insulin-stimulated glucose uptake in 3T3-L1 adipocytes without activating the peroxisome proliferator-activated receptor-gamma agonist. They decreased triacylglycerol accumulation in adipocytes. In addition, glyceollins slightly improved glucose-stimulated insulin secretion without palmitate treatment in Min6 cells, and they potentiated insulinotropic actions when 500 microM palmitate was used to induce beta-cell dysfunction. This was associated with decreased beta-cell apoptosis because of the attenuation of endoplasmic reticulum stress, as determined by mRNA levels of XBP-1, ATF-4, ATF-6, and CHOP. Glyceollins also potentiated GLP-1 secretion to enhance insulinotropic actions in enteroendocrine cells. In conclusion, glyceollins help normalize glucose homeostasis by potentiating beta-cell function and survival and improving glucose utilization in adipocytes.

The pairing of a selective estrogen receptor modulator, bazedoxifene, with conjugated estrogens as a new paradigm for the treatment of menopausal symptoms and osteoporosis prevention

The menopausal transition is associated with decreased ovarian function and concomitant decline in estrogen production, which may result in physiological effects such as hot flashes, reduced bone mass, and altered lipid profile. It is well established that these unfavorable changes are effectively offset with estrogen therapy (ET) or, in women with a uterus, estrogens in combination with a progestin (hormone therapy). Selective estrogen receptor (ER) modulators (SERMs), which exhibit both ER agonist and antagonist activities depending on the target tissue, have been regarded as offering the potential to provide the benefits of ET and hormone therapy with an improved safety and tolerability profile. To date, no SERM alone has demonstrated an ideal benefit-risk profile for menopausal therapy. The tissue-selective estrogen complex, or the pairing of a SERM with estrogens, may provide an optimal blend of ER agonist and antagonist activities. We evaluated the physiological profile of this novel therapeutic paradigm by using various in vivo models to assess uterine, vasomotor, lipid, and skeletal responses to a tissue-selective estrogen complex partnering bazedoxifene with conjugated estrogens (CE). Bazedoxifene at 3.0 mg/kg effectively antagonized CE-induced uterine stimulation without reversing the positive effects of CE on vasomotor instability. When paired with CE, bazedoxifene at 3.0 mg/kg reduced total cholesterol levels by up to 20% compared with CE alone and significantly increased total bone density relative to control. These preclinical findings showed that the appropriate dose combination of bazedoxifene/CE exhibits positive vasomotor, lipid, and skeletal responses with minimal uterine stimulation.

Hormone replacement therapy use and the risk of stroke

OBJECTIVES

Randomised trials reported an increase risk of stroke with an estrogen plus progestogen formulation of hormone replacement therapy (HRT). A recent trial also reported an increased risk with tibolone, a selective tissue estrogenic activity regulator.

METHODS

We used the General Practice Research Database to conduct a case-control study within a cohort of women aged 50-79 between January 1987 and October 2006, without history of stroke prior to cohort entry. We identified all cases of stroke occurring during the study period and selected up to four controls matched to each case on age, general practice and year of start in the practice. Information on HRT use during the year preceding the index date was obtained. Conditional logistic regression was used to estimate the rate ratios of stroke associated with current use of the different HRTs.

RESULTS

The cohort included 870,286 women, of whom 15,710 experienced a stroke during follow-up and were matched to 59,958 controls. The adjusted rate ratio of stroke associated with current use of tibolone relative to non-use of HRT was 1.08 (95% CI: 0.82-1.44). The rate ratios with current use of estrogens alone and estrogen plus progestogen were 1.26 (95% CI: 1.10-1.45) and 1.19 (95% CI: 1.05-1.36) respectively.

CONCLUSIONS

We found no evidence of an elevated risk of stroke associated with the use of tibolone, although the low number of subjects using tibolone does not permit to rule out a small risk. The small elevated risk of stroke with estrogens or estrogens plus progestogen is consistent with that reported in randomised trials.

Estrogen receptor beta: expression profile and possible anti-inflammatory role in disease

Estrogen receptor (ER) beta agonists have been demonstrated to possess anti-inflammatory properties in inflammatory disease models. The objective of this study was to determine whether ERbeta agonists affect in vitro and in vivo preclinical models of asthma. mRNA expression assays were validated in human and rodent tissue panels. These assays were then used to measure expression in human cells and our characterized rat model of allergic asthma. ERB-041 [7-ethenyl-2-(3-fluoro-4-hydroxyphenyl)-1,3-benzoxazol-5-ol], an ERbeta agonist, was profiled on cytokine release from interleukin-1beta-stimulated human airway smooth muscle (HASM) cells and in the rodent asthma model. Although ERbeta expression was demonstrated at the gene and protein level in HASM cells, the agonist failed to have an impact on the inflammatory response. Similarly, in vivo, we observed temporal modulation of ERbeta expression after antigen challenge. However, the agonist failed to have an impact on the model endpoints such as airway inflammation, even though plasma levels reflected linear compound exposure and was associated with an increase in receptor activation after drug administration. In these modeling systems of airway inflammation, an ERbeta agonist was ineffective. Although ERbeta agonists are anti-inflammatory in certain models, this novel study would suggest that they would not be clinically useful in the treatment of asthma.

Progesterone: Therapeutic opportunities for neuroprotection and myelin repair

Progesterone and its metabolites promote the viability of neurons in the brain and spinal cord. Their neuroprotective effects have been documented in different lesion models, including traumatic brain injury (TBI), experimentally induced ischemia, spinal cord lesions and a genetic model of motoneuron disease. Progesterone plays an important role in developmental myelination and in myelin repair, and the aging nervous system appears to remain sensitive to some of progesterone's beneficial effects. Thus, the hormone may promote neuroregeneration by several different actions by reducing inflammation, swelling and apoptosis, thereby increasing the survival of neurons, and by promoting the formation of new myelin sheaths. Recognition of the important pleiotropic effects of progesterone opens novel perspectives for the treatment of brain lesions and diseases of the nervous system. Over the last decade, there have been a growing number of studies showing that exogenous administration of progesterone or some of its metabolites can be successfully used to treat traumatic brain and spinal cord injury, as well as ischemic stroke. Progesterone can also be synthesized by neurons and by glial cells within the nervous system. This finding opens the way for a promising therapeutic strategy, the use of pharmacological agents, such as ligands of the translocator protein (18 kDa) (TSPO; the former peripheral benzodiazepine receptor or PBR), to locally increase the synthesis of steroids with neuroprotective and neuroregenerative properties. A concept is emerging that progesterone may exert different actions and use different signaling mechanisms in normal and injured neural tissue.

Picking a bone with contemporary osteoporosis management: Nutrient strategies to enhance skeletal integrity

Epidemic rates of osteoporosis in the western world have yielded intense efforts to develop management approaches to combat this potentially devastating disorder; recent research has unveiled innovative strategies which hold considerable promise for prevention of skeletal compromise and amelioration of suboptimal bone health. According to many algorithms and practice directives, the contemporary assessment and management of osteoporosis focuses heavily on determination of fracture risk and pharmaceutical intervention for those patients deemed to be at high risk. While routine recommendations for calcium and vitamin D have been incorporated into most regimens, disproportionately little attention has been given to recent research elucidating improved bone health and diminution in fracture rates experienced by patients receiving specific nutrients. In mainstream medical practice, clinical analysis and management of nutritional or dietary issues is sometimes perceived as unconventional, primitive or unsophisticated health care. Recent evidence-based research, however, supports intervention with adequate amounts of specific nutrients including vitamin D, strontium, vitamin K, and essential fatty acids in the prevention and primary management of osteoporosis.

Sacral insufficiency fractures: current concepts of management

BACKGROUND

Sacral insufficiency fractures (SIFs) are often overlooked in elderly patients presenting with low back and pelvic pain following no or minimal trauma.

OBJECTIVE

The aim of this review is to raise awareness and outline the clinical presentation, methods of diagnosis and treatment of SIFs.

DISCUSSION

Insufficiency fractures represent a special category of stress fractures that occur in bones with reduced mineral content and elastic resistance. SIFs, a well-defined subgroup of the latter group, are not uncommon, but lack of clinical suspicion results in many being undiagnosed. SIFs are set to become an important clinical entity of both social and economic significance as the Western population ages. Subtle clinical presentations and signs coupled with radiographic findings that can mimic other unrelated or overlapping conditions, such as sacroiliac joint infection, spinal stenosis and metastatic bone disease, often make SIF diagnosis a challenge. The aim of this review is to increase awareness among clinicians, highlighting SIFs as an important differential diagnosis to be considered when patients present with low back and pelvic pain and subsequently allow prompt management. The paper provides an overview of epidemiology, anatomical considerations, relevant pathophysiology and risk factors, presenting symptoms and signs, investigations and imaging techniques, differential diagnoses and current treatment methods available for the management of SIFs.

Osteoporosis in Health and Disease: A Dermatologist's Perspective

Osteoporosis affects more than 75 million people in the United States, Asia, and Europe. Osteoporosis results from a combination of genetic and environmental factors that contribute to peak bone mass and the rate of bone loss. These factors include medications, diet, race, sex, lifestyle, and physical activity. The management of osteoporosis can be complicated by simultaneous treatment of other diseases. For dermatologists, the use of long-term oral corticosteroids for the management of immunobullous and blistering diseases is of particular importance. Although these treatment modalities are potentially lifesaving for patients, the side effects can be dangerous. This article examines the pathophysiology, clinical course, and treatments for osteoporosis and the special considerations that arise when managing patients using corticosteroids.

Emerging Selective Estrogen Receptor Modulators

Menopause, regardless of age at onset, is associated with a marked increase in coronary heart disease (CHD) risk. On the basis of epidemiological studies that demonstrated mainly positive effects of postmenopausal hormone therapy on CHD as well as on risk markers of CHD, it has been suggested that CHD could be prevented in postmenopausal women with long-term hormone therapy. However, since the publications of the Heart and Estrogen/progestin Replacement Study and the Women's Health Initiative trial, prescription of hormone therapy for the prevention of CHD has become controversial. Major efforts have been made to identify alternatives for hormone therapy. Compounds suggested have included selective estrogen receptor modulators (SERMs), which represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This pharmacological profile may offer the opportunity to dissociate favourable estrogenic effects on the bone and cardiovascular system from unfavourable stimulatory effects on the breast and endometrium. Two SERMs presently on the market are tamoxifen and raloxifene. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. These trials found fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a second-generation SERM that has been shown to prevent osteoporotic fractures, is safe for the endometrium and holds high promise for the prevention of breast cancer. The effect of raloxifene on CHD is still uncertain. On the basis of the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, raloxifene may offer some protection to women with CHD or to those who are at high risk of CHD. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Next-generation SERMs taken into clinical development include idoxifene, droloxifene, ospemifene, arzoxifene, acolbifene/EM-800, levormeloxifene, lasofoxifene, bazedoxifene and HMR 3339. The aim is to find a compound with the ideal profile, that is, alleviation of climacteric symptoms and prevention of osteoporotic fractures, but without an adverse effect on the breast and endometrium, and no negative effect or even a beneficial effect on the cardiovascular system and the brain. Currently, limited data are available with regard to these next-generation SERMs and CHD. Nevertheless, some of these novel agents provide arguments for continuing the search for an ideal SERM.