Bone ultrasonometric features and growth hormone secretion in asthmatic patients during chronic inhaled corticosteroid therapy

Interrelationship Between Obstructive Sleep Apnea Syndrome and Severe Asthma: From Endo-Phenotype to Clinical Aspects

Sleep-related breathing disorders (SBDs) are characterized by abnormal respiration during sleep. Obstructive sleep apnea (OSA), a common SBD increasingly recognized by physicians, is characterized by recurrent episodes of partial or complete closure of the upper airway resulting in disturbed breathing during sleep. OSA syndrome (OSAS) is associated with decreased patients' quality of life (QoL) and the presence of significant comorbidities, such as daytime sleepiness. Similarly to what seen for OSAS, the prevalence of asthma has been steadily rising in recent years. Interestingly, severe asthma (SA) patients are also affected by poor sleep quality—often attributed to nocturnal worsening of their asthma—and increased daytime sleepiness and snoring compared to the general population. The fact that such symptoms are also found in OSAS, and that these two conditions share common risk factors, such as obesity, rhinitis, and gastroesophageal reflux, has led many to postulate an association between these two conditions. Specifically, it has been proposed a bidirectional correlation between SA and OSAS, with a mutual negative effect in term of disease severity. According to this model, OSAS not only acts as an independent risk factor of asthma exacerbations, but its co-existence can also worsen asthma symptoms, and the same is true for asthma with respect to OSAS. In this comprehensive review, we summarize past and present studies on the interrelationship between OSAS and SA, from endo-phenotype to clinical aspects, highlighting possible implications for clinical practice and future research directions.

Effects of Medical Treatment of Prostate Cancer on Bone Health

Medical treatment of prostate cancer (PC) is multidisciplinary, resulting in prolonged survival. Androgen-deprivation therapy (ADT) can have negative effects on skeletal metabolism, particularly if combined with glucocorticoids. We discuss the pathophysiology and effects of ADT and glucocorticoids on skeletal endpoints, as well as the awareness and management of bone fragility. Coadministration of glucocorticoids is necessary with abiraterone because this causes a novel acquired form of 17-hydroxylase deficiency and synergistically increases the risk of fracture by affecting bone quality. Bone antiresorptive agents [selective estrogen receptor modulators (SERMS), bisphosphonates, and denosumab] increase bone mineral density (BMD) and in some instances reduce fracture risk in PC patients on ADT. Awareness and management of bone health in PC can be improved by integrating endocrinologists into the multidisciplinary PC team.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Growth hormone deficiency in treated acromegaly and active Cushing's syndrome

Growth hormone deficiency (GHD) in adults is characterized by reduced quality of life and physical fitness, skeletal fragility, increased weight and cardiovascular risk. It may be found in (over-) treated acromegaly as well as in active Cushing's syndrome. Hypopituitarism may develop in patients after definitive treatment of acromegaly, although the exact prevalence of GHD in this population is still uncertain because of limited awareness, and scarce and conflicting data so far available. Because GHD associated with acromegaly and Cushing's syndrome may yield adverse consequences on similar target systems, the final outcomes of some complications of both acromegaly and Cushing's syndrome may be further affected by the occurrence of GHD. It is still largely unknown, however, whether GHD in patients with post-acromegaly or active Cushing's syndrome (e.g. pharmacologic glucocorticoid treatment) may benefit from GH replacement. We review the diagnostic, clinical and therapeutic aspects of GHD in adults treated for acromegaly and in those with active Cushing's syndrome.

Glucocorticoids and the regulation of growth hormone secretion

Glucocorticoids modulate the secretion of growth hormone (GH) by various and competing effects on the hypothalamus and pituitary gland. The final effects of this modulation depend on hormone concentrations and the duration of exposure. The traditional hypothesis is that chronically raised levels of glucocorticoids suppress the secretion of GH. However, a functional impairment of the GH reserve might also be observed in patients with low levels of glucocorticoids, such as those with secondary hypoadrenalism, which is consistent with the model of biphasic dose-dependent effects of glucocorticoids on the somatotropic axis. This Review updates our current understanding of the mechanisms underlying the effects of glucocorticoids on the secretion of GH and the clinical implications of the dual action of glucocorticoids on the GH reserve in humans. This Review will also address the potential diagnostic and therapeutic implications of GH for patients with a deficiency or excess of glucocorticoids.

Corticosteroid resistance and novel anti-inflammatory therapies in chronic obstructive pulmonary disease: current evidence and future direction

Corticosteroids are widely used in the treatment of chronic obstructive pulmonary disease (COPD). However, in contrast to their use in mild-to-moderate asthma, they are much less effective in enhancing lung function and have little or no effect on controlling the underlying chronic inflammation. In most clinical trials in COPD patients, corticosteroids have shown little benefit as monotherapy, but have shown a greater clinical effect in combination with long-acting bronchodilators. Several mechanisms of corticosteroid resistance have been postulated, including a reduction in histone deacetylase (HDAC)-2 activity and expression, impaired corticosteroid activation of the glucocorticoid receptor (GR) and increased pro-inflammatory signalling pathways. Reversal of corticosteroid resistance in COPD patients by restoring HDAC2 levels has proved effective in a small study, and long-term studies are needed to determine whether novel HDAC2 activators or theophylline improve disease progression, exacerbations or mortality. Advances in the understanding of the cellular and molecular mechanisms of corticosteroid resistance in COPD pathophysiology have supported the development of new emerging classes of anti-inflammatory drugs in COPD treatment. These include treatments such as inhibitors of phosphoinositide-3-kinase-delta (PI3Kδ), phosphodiesterase-4 (PDE4), p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB), and therapeutic agents such as chemokine receptor antagonists. Of these, PI3Kδ, PDE4, p38 MAPK inhibitors and chemokine receptor antagonists are in clinical patient trials. Of importance, patient adverse effects associated with oral administration of these novel agents needs to be addressed in order to optimize therapy and patient compliance. Combinations of these drugs with corticosteroids may have additional benefits.

The association of low bone mineral density with systemic inflammation in clinically stable COPD

Chronic obstructive pulmonary disease (COPD) is known to be a systemic inflammatory disease which affects the function of many organs, and the low bone mineral density (BMD) may be the result of systemic inflammation. The aim of the present study was to explore the association of BMD with systemic inflammation in patients with clinically stable COPD. BMD and inflammatory markers, including C-reactive protein, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), were determined in all the recruited patients with clinically stable COPD. The patients were classified according to T scores, and the relationship between BMD with markers of systemic inflammation and that with other osteoporosis risk factors was assessed. There were no differences in age, female sex, body composition, tobacco exposure, and the use of respiratory medications among these groups. As the abnormality of BMD went severer, COPD patients with osteoporosis had significantly higher levels of systemic inflammation than those with either normal BMD or osteopenia. The presence of systemic inflammation was associated with a greater likelihood of low BMD, and multivariate logistic regression analysis showed that TNF-α and IL-6 were independent predictors of low BMD. It can be concluded that systemic inflammation is a significantly independent predictor of low BMD in patients with clinically stable COPD.

Effect of body mass index on peak growth hormone response to provocative testing in children with short stature

CONTEXT

Obesity is associated with decreased spontaneous and stimulated GH secretion, but the effect of body mass index (BMI) on results of GH stimulation testing in children with short stature is not known.

OBJECTIVE

The aim of the study was to determine the impact of BMI on peak GH to provocative testing in children with short stature.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective review of provocative GH testing performed in 116 children 2-18 yr old in the ambulatory clinic of the Pediatric Endocrinology Unit at the Massachusetts General Hospital from 2004-2008.

MAIN OUTCOME MEASURES

The main outcome measure was peak stimulated GH. Height, weight, IGF-I, and IGF-binding protein 3 were also measured.

RESULTS

In univariate regression analysis, BMI sd score (BMI SDS) was inversely associated with natural log (ln) peak GH to provocative testing (P = 0.002), whereas height SDS, ln IGF-I, and IGF-binding protein 3 were not significantly associated with ln peak GH. After controlling for age, gender, BMI, and pubertal status, BMI (P = 0.002) remained independently associated with ln peak GH. BMI SDS significantly influenced the likelihood of diagnosis of GH deficiency using peak GH cutoffs of 10, 7, and 5 microg/liter.

CONCLUSION

In children with short stature, BMI affects peak stimulated GH and should be considered when interpreting GH testing. Higher BMI SDS, even within the normal range, may lead to overdiagnosis of GH deficiency.

Growth hormone, insulin-like growth factors, and the skeleton

GH and IGF-I are important regulators of bone homeostasis and are central to the achievement of normal longitudinal bone growth and bone mass. Although GH may act directly on skeletal cells, most of its effects are mediated by IGF-I, which is present in the systemic circulation and is synthesized by peripheral tissues. The availability of IGF-I is regulated by IGF binding proteins. IGF-I enhances the differentiated function of the osteoblast and bone formation. Adult GH deficiency causes low bone turnover osteoporosis with high risk of vertebral and nonvertebral fractures, and the low bone mass can be partially reversed by GH replacement. Acromegaly is characterized by high bone turnover, which can lead to bone loss and vertebral fractures, particularly in patients with coexistent hypogonadism. GH and IGF-I secretion are decreased in aging individuals, and abnormalities in the GH/IGF-I axis play a role in the pathogenesis of the osteoporosis of anorexia nervosa and after glucocorticoid exposure.

Prevalência de desvios-padrão determinados pela ultra-sonometria de calcâneo e sua associação com índice de massa corporal e idade em mulheres pós-menopáusicas residentes em Manaus-AM

Resumo O envelhecimento populacional aumenta o número de idosos e a prevalência de doenças como osteoporose, que está associada a fraturas. Para esse tipo de avaliação, a ultra-sonometria de calcâneo (USO) poderia ser uma boa alternativa, porque é barata, fácil de ser medida e não expõe os indivíduos à radiação. O estudo apresentado estimou a prevalência de três diferentes grupos de desvio-padrão (DP<-1, DP<-1<-2,5 e DP<-2,5), determinados pela USO e sua associação com idade e índice de massa corporal (IMC) em mulheres idosas que vivem na comunidade de Manaus-AM. O delineamento foi do tipo retrospectivo, observacional e descritivo, em 997 mulheres que fizeram o exame de USO de calcâneo e foram classificadas nos três grupos (DP <-2,5, SD >-1<-2,5DP e SD <-1). A prevalência dos grupos DP foi: DP<-2,5 = 23,0% (229), DP<-1<2,5 = 53,2% (530) e DP<-2,5 = 23,6% (238). Mulheres com DP<-2,5 apresentaram valores de IMC significativamente mais baixos (p=0,016) e também idade mais elevada (p=0,007). Os resultados sugerem associação da USO com IMC e idade avançada, corroborando estudos previamente publicados na literatura. O estudo corrobora a possibilidade de utilização da USO em levantamentos epidemiológicos.

Glucocorticoid-induced osteoporosis: an update

Glucocorticoid-induced osteoporosis occurs in two phases: a rapid, early phase in which bone mineral density is reduced, possibly as a result of excessive bone resorption, and a slower, progressive phase in which bone mineral density declines because of impaired bone formation. Although the indirect effects of glucocorticoids on bone are evident, their direct effects on osteoblasts, osteoclasts and osteocytes are primarily operative in the pathogenesis of glucocorticoid-induced osteoporosis. The management of patients exposed to glucocorticoids includes general health measures, sufficient calcium and vitamin D, and reducing the therapeutic regimen to the minimal effective dose. The gold standard in the pharmacological treatment of glucocorticoid-induced osteoporosis in postmenopausal women involves the use of bisphosphonates, which should be started soon after beginning chronic glucocorticoid therapy. Anabolic and alternative therapeutic strategies are currently under investigation in glucocorticoid-induced osteoporosis.