Modification of Muscle-Related Hormones in Women with Obesity: Potential Impact on Bone Metabolism (original) (raw)
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Hormone Molecular Biology and Clinical Investigation, 2014
The belief that obesity is protective against osteoporosis has recently been revised. In fact, the latest epidemiologic and clinical studies show that a high level of fat mass, but also reduced muscle mass, might be a risk factor for osteoporosis and fragility fractures. Furthermore, increasing evidence seems to indicate that different components such as myokines, adipokines and growth factors, released by both fat and muscle tissues, could play a key role in the regulation of skeletal health and in low bone mineral density and, thus, in osteoporosis development. This review considers old and recent data in the literature to further evaluate the relationship between fat, bone and muscle tissue.
Determinants of bone mineral density in obese premenopausal women
Bone, 2011
Despite being a risk factor for cardiovascular disease and diabetes mellitus, obesity has been thought to protect against osteoporosis. However, recent studies have demonstrated a differential impact of specific fat compartments on bone mineral density (BMD) with visceral adipose tissue (VAT) having potential detrimental effects on BMD. Visceral obesity is also associated with dysregulation of the GH/IGF-1 axis, an important regulator of bone homeostasis. The purpose of our study was to evaluate the differential effects of abdominal fat depots and muscle, vitamin D, and hormonal determinants, including insulin-like growth factor-1 (IGF-1), testosterone, and estradiol, on trabecular BMD of the lumbar spine. We studied 68 healthy obese premenopausal women (mean BMI, 36.7 ± 4.2 kg/m 2 ). Quantitative computed tomography (QCT) was used to assess body composition and lumbar trabecular BMD. There was an inverse association between BMD and VAT, independent of age and BMI (p = 0.003). IGF-1 correlated positively with BMD and negatively with VAT and, in stepwise multivariate regression modeling, was the strongest predictor of BMD and procollagen type 1 amino-terminal propeptide (P1NP). Thigh muscle cross sectional area (CSA) and thigh muscle density were also associated with BMD (p b 0.05), but 25-hydroxyvitamin D [25(OH)D], testosterone, free testosterone, and estradiol levels were not. 25(OH)D was associated inversely with BMI, total, and subcutaneous abdominal adipose tissue (p b 0.05). These findings support the hypothesis that VAT exerts detrimental effects, whereas muscle mass exerts positive effects on BMD in premenopausal obese women. Moreover, our findings suggest that IGF-1 may be a mediator of the deleterious effects of VAT on bone health through effects on bone formation.
Ageing research reviews, 2014
While sarcopenia and sarcopenic obesity have been recognized in the last decade, a combined concept to include decreased muscle mass and strength, as well as decreased bone mass with coexistence of adiposity is discussed here. We introduce a new term, osteopenic obesity, and operationalize its meaning within the context of osteopenia and obesity. Next, we consolidate osteopenic obesity with the already existing and more familiar term, sarcopenic obesity, and delineate the resulting combined condition assigning it the term osteosarcopenic obesity. Identification and possible diagnosis of each condition are discussed, as well as the interactions of muscle, fat and bone tissues on cellular level, considering their endocrine features. Special emphasis is placed on the mesenchymal stem cell commitment into osteoblastogenic, adipogenic and myogenic lineages and causes of its deregulation. Based on the presented evidence and as expounded within the text, it is reasonable to say that under ...
Medical Research Journal, 2019
Recent studies in mice and humans have shown the tight connection between bone and muscle tissues. Physical activity affects the function of osteocytes, mature bone cells, stimulating the synthesis of several hormone-like myokines in skeletal muscles. Anabolic action of physical exercise on bone is mediated by a myokine called irisin. This protein was initially assigned to regulate glucose homeostasis in humans but recently the influence of irisin on bone and adipose tissue metabolism was also demonstrated. In the human blood, irisin occurs in different forms, free or complexed, glycosylated and non-glycosylated which makes a reliable and reproducible measurement of this protein a crucial issue for the clinical interpretation of experimental findings. In humans, irisin was shown to inversely correlate with the prevalence of bone fractures. Data obtained so far suggest that irisin could be a potential target for the treatment of osteoporosis and play an important role in the bone healing process.
Journal of Pediatric Endocrinology and Metabolism, 2000
Obesity is a chronic inflammatory condition with numerous metabolic consequences to the organism, highlighting its influence on bone mass. Therefore, the aim of this study was to verify the role of visceral fat, leptin, adiponectin and ghrelin on bone mineral density in obese post-puberty adolescents girls, submitted to an interdisciplinary therapy. The study involved 20 post-puberty obese adolescent girls: 16 ± 1.5 years of age, 98.9 ± 15.8 kg (weight), 1.60 ± 0.72 m (height) and 37.2 ± 4.8 kg/m 2 [body mass index (BMI)]. Anthropometric measurements, body composition, visceral fat, subcutaneous fat, bone mineral density and content were determined. Ghrelin, leptin and adiponectin were analyzed and the leptin/adiponectin ratio was calculated. Our findings showed a significant increase in adiponectin concentration and a reduction in body weight, BMI, total fat mass, visceral and subcutaneous fat. In addition, ghrelin (r 2 =-0.53; p = 0.02) visceral fat (r 2 =-0.46, p = 0.04) (r 2-0.66, p = 0.001) and leptin/adiponectin ratio (r 2-0.56, p = 0.01) were negative predictors for bone mineral density and content in obese adolescent girls, respectively. It provides a novel physiologically concept that may shed light on the etiology of osteoporosis and help to identify new therapeutic targets. However this should be confirmed in a large cohort study.
Metabolites
Variations in levels of some adipokines, myokines, osteokines, hepatokines and inflammatory cytokines contribute to abnormal glucose and lipid metabolism. The aim of this study was to determine the pattern of adiponectin, osteocalcin (OCN), irisin, FGF-21, and MCP-1 according to the body size phenotype of middle-aged women, and their associations with BMI, visceral adipose tissue (VAT), and HOMA-IR. A cross-sectional study in 265 women aged from 40 to 65 years was performed. The biochemical characteristics were evaluated in metabolically healthy normal weight, metabolically unhealthy normal weight, metabolically healthy obese, and metabolically unhealthy obese women. There was an association of OCN with BMI (r = −0.107; p = 0.047); adiponectin with BMI (r = −0.217; p = 0.001), insulin (r = −0.415; p = 0.0001), HOMA-IR (r = −0.429; p = 0.0001), and VAT (r = −0.134; p = 0.025); irisin with BMI (r = 0.604; p = 0.001), insulin (r = 0.446; p = 0.0001), HOMA-IR (r = 0.452; p = 0.0001), an...
Medical Research Journal, 2018
Recent studies in mice and humans have shown the tight connection between bone and muscle tissues. Physical activity affects the function of osteocytes, mature bone cells, stimulating synthesis of several hormone-like myokines in skeletal muscles. Anabolic action of physical exercise on bone is mediated by a myokine called irisin. This protein was initially assigned to regulate glucose homeostasis in humans but recently the influence of irisin on bone and adipose tissue metabolism was also demonstrated. In the human blood irisin occurs in different forms: free or complexed, glycosylated and non-glycosylated which makes reliable and reproducible measurement of this protein a crucial issue for the clinical interpretation of experimental findings. In humans irisin was shown to inversely correlate with the prevalence of bone fractures. Data obtained so far suggest that irisin could be a potential target for treatment of osteoporosis and play an important role in the bone healing process.
2004
The interaction between obesity and bone metabolism is complex. The effects of fat on the skeleton are mediated by both mechanical and biochemical factors. Though obesity is characterized by higher bone mineral density, studies conducted on bone microarchitecture have produced conflicting results. The majority of studies indicate that obesity has a positive effect on skeletal strength, even though most likely the effects are site-dependent and, in fact, obese individuals might be at risk of certain types of fractures. Mechanical loading and higher lean mass are associated with improved outcomes, whereas systemic inflammation, observed especially with abdominal obesity, may exert negative effects. Weight loss interventions likely lead to bone loss over time. Pharmacological treatment options seem to be safe in terms of skeletal health; however, the skeletal effects of bariatric surgery are dependent on the type of surgical procedure. Malabsorptive procedures are associated with higher short-term adverse effects on bone health. In this narrative review, we discuss the effects of obesity and weight loss interventions on skeletal health.
International Journal of Clinical Practice, 2010
Background: Obese individuals often present comorbidities while they appear protected against the development of osteoporosis. However, few and contradictory data are now available on skeletal modifications in obese patients. The aim of this study was to characterise bone mineral density (BMD) in overweight (BMI > 25 < 29.9) and obese (BMI > 30) patients.Methods: We selected 398 patients (291 women, 107 men, age 44.1 + 14.2 years, BMI 35.8 + 5.9 kg/m2) who underwent clinical examination, blood tests and examination of body composition. Subjects with chronic conditions or taking medications interfering with bone metabolism, hormonal and nutritional status and recent weight loss were excluded.Results: Interestingly, 37% (n = 146) of this population showed a significantly lower than expected lumbar BMD: 33% (n = 98) of women showed a T-score −1.84 ± 0.71, and 45% (n = 48) of men showed a T-score −1.88 ± 0.64. When the population was divided into subgroups based on different BMI, it was noted that overweight (BMI > 25 < 29.9) was neutral or protective for BMD, whereas obesity (BMI > 30) was associated with a low bone mass, compatible with a diagnosis of osteoporosis. No differences were observed in hormones and lipid profiles among subgroups.Conclusions: Our results indicate that a subpopulation of obese patients has a significant low lumbar BMD than expected for age. Thus, a careful characterisation of skeletal metabolism might be useful in all obese individuals to avoid fragility fractures later in life.
Cytokines and Hormones That Contribute to the Positive Association between Fat and Bone
Frontiers in endocrinology, 2014
The positive association between body weight and bone density has been established in numerous laboratory and clinical studies. Apart from the direct effect of soft tissue mass on bone through skeletal loading, a number of cytokines and hormones contribute to the positive association between adipose and bone tissue, acting either locally in sites where cells of the two tissues are adjacent to each other or systemically through the circulation. The current review describes the effects of such local and systemic factors on bone physiology. One class of factors are the adipocyte-secreted peptides (adipokines), which affect bone turnover through a combination of direct effects in bone cells and indirect mechanisms mediated by the central nervous system. Another source of hormones that contribute to the coupling between fat and bone tissue are beta cells of the pancreas. Insulin, amylin, and preptin are co-secreted from pancreatic beta cells in response to increased glucose levels after ...