Novel Adipokines and Their Role in Bone Metabolism: A Narrative Review

Bone Marrow Adipocytes as Novel Regulators of Metabolic Homeostasis: Clinical Consequences of Bone Marrow Adiposity

PURPOSE OF REVIEW

Bone marrow adipose tissue is a distinctive fat depot located within the skeleton, with the potential to influence both local and systemic metabolic processes. Although significant strides have been made in understanding bone marrow adipose tissue over the past decade, many questions remain regarding their precise lineage and functional roles.

RECENT FINDINGS

Recent studies have highlighted bone marrow adipose tissue's involvement in continuous cross-talk with other organs and systems, exerting both endocrine and paracrine functions that play a crucial role in metabolic homeostasis, skeletal remodeling, hematopoiesis, and the progression of bone metastases. The advancement of imaging techniques, particularly cross-sectional imaging, has profoundly expanded our understanding of the complexities beyond the traditional view of bone marrow adipose tissue as an inert depot. Notably, marrow adipocytes are anatomically and functionally distinct from brown, beige, and classic white adipocytes. Emerging evidence suggests that bone marrow adipocytes, bone marrow adipose tissue originate from the differentiation of bone marrow mesenchymal stromal cells; however, they appear to be a heterogeneous population with varying metabolic profiles, lipid compositions, secretory properties, and functional responses depending on their specific location within the bone marrow. This review provides an up-to-date synthesis of current knowledge on bone marrow adipocytes, emphasizing the relationships between bone marrow adipogenesis and factors such as aging, osteoporosis, obesity, and bone marrow tumors or metastases, thereby elucidating the mechanisms underlying musculoskeletal pathophysiology.

Adipokine dysregulation as an underlying pathology for diffuse ectopic ossification of spinal posterior longitudinal ligament in patients with obesity

BACKGROUND CONTEXT

Growing evidence suggests that obesity is implicated in the progression of heterotopic ossification of the posterior longitudinal ligament of the spine (OPLL), a major cause of myelopathy in Asians. However, it remains unclear whether dysregulation of adipokine production due to fat accumulation contributes to OPLL progression.

PURPOSE

To determine whether adipose-derived biochemical signals are associated with OPLL development or severity.

STUDY DESIGN/SETTING

A nationwide, multicenter, case-control study.

PATIENT SAMPLE

Patients with symptomatic thoracic OPLL (T-OPLL) who received treatment between June 2017 and March 2021 and 111 controls without OPLL.

OUTCOME MEASURES

OPLL severity index based on whole-spine computed tomography.

METHODS

Serum concentrations of adipokines, including leptin (Lep), tumor necrosis factor α (TNFα), and adiponectin (Adpn), as well as the Adpn/Lep ratio-an indicator of adipokine production dysregulation-were compared between the multiple-region OPLL and the single-region OPLL groups. Regression analysis was performed to examine the correlation between adipokine concentrations and OPLL severity index, which was calculated using whole-spine computed tomography images of 77 patients with T-OPLL within 3 years of onset. Using propensity score matching, the adipokine profiles of 59 patients with T-OPLL were compared with those of 59 non-OPLL controls.

RESULTS

Patients with multiple-region OPLL exhibited a higher body mass index (BMI), lower serum Adpn/Lep ratio, and higher serum concentration of osteocalcin (OCN) than those with single-region OPLL. The OPLL severity index exhibited a weak positive correlation with BMI and serum Lep levels and a weak negative correlation with the Adpn/Lep ratio. Serum TNFα and OCN concentrations were significantly higher in patients with T-OPLL than in controls with similar age, sex, and BMI.

CONCLUSIONS

Patients with diffuse OPLL over the entire spine are often metabolically obese with low Adpn/Lep ratios. In patients with OPLL, TNFα and OCN serum concentrations were essentially elevated regardless of obesity, suggesting a potential association with OPLL development. Considering the absence of therapeutic drugs for OPLL, the findings presented herein offer valuable insights that can aid in identifying therapeutic targets and formulating strategies to impede its progression.

Effect of adipose tissue on the development of multiple myeloma

Multiple myeloma (MM), also referred to as Kahler's disease, is a cancer characterized by the uncontrolled growth of abnormal plasma cells and is associated with alterations in the bone tissue microenvironment. Bone marrow adipose tissue (BMAT), which comprises approximately ten percent of total body fat, can influence the progression, survival, and drug resistance of MM cells through paracrine, hormonal, and metabolic pathways. Obesity can lead to an increase in BMAT mass, which not only disrupts bone metabolism but also reduces bone density, potentially progressing from monoclonal gammopathy of undetermined significance, a benign condition, to MM. A range of factors, including impaired fatty acid metabolism, increased production of adipokines that support myeloma, and heightened expression of oncogenic microRNAs in multiple myeloma, contribute to the progression of this incurable blood cancer. To better understand the relationship between excess adipose tissue accumulation and the risk of developing multiple myeloma, a comprehensive review of published data was conducted.

An integrated view of the pathophysiological crosstalk between adipose tissue, bone and cardiovascular system in men and women

BACKGROUND

Obesity, bone-related and cardiovascular diseases (CVD) are among the leading global health concerns. Growing evidence suggests that these conditions share common pathophysiological pathways and disease outcomes. PATHOGENETIC INTERACTIONS OF OBESITY, CVD AND BONE-RELATED DISEASES: Obesity is a well-established risk factor for atherosclerotic CVD (ASCVD), as dysfunctional ectopic adipose tissue may produce endocrine/paracrine hormones modulating metabolic processes and inflammation, predisposing to ASCVD. Although obesityhas been considered a protective factor for bone loss, it may lead to osteoporosis development and increased fracture risk at specific sites. Biological and epidemiological evidence has demonstrated the existence of a dynamic relationship between ASCVD and osteoporosis, since atherosclerotic calcification and bone mineralization share common pathophysiological mechanisms. Therefore, addressing ASCVD, obesity, and bone-related diseases requires multiple-level approach, which involve accurate screening, lifestyle modifications and pharmacological interventions.The current evidence about the pathophysiological relationships between obesity, bone-related diseases and ASCVD is discussed herein, highlighting common risk factors, proposed biomolecular mechanisms, clinical outcomes, lifestyle changes and pharmacological treatments.

CONCLUSIONS

As populations become increasingly older and obese, understanding the correlation within this triad highlights an unmet clinical need. Applying this knowledge would help to reduce both societal and individual costs, while supporting the development of novel preventive, diagnostic and therapeutic strategies to reduce morbidity and disability associated with cardio-metabolic and bone-related diseases.

Leptin physiology and pathophysiology in energy homeostasis, immune function, neuroendocrine regulation and bone health

Since its discovery and over the past thirty years, extensive research has significantly expanded our understanding of leptin and its diverse roles in human physiology, pathophysiology and therapeutics. A prototypical adipokine initially identified for its critical function in appetite regulation and energy homeostasis, leptin has been revealed to also exert profound effects on the hypothalamic-pituitary-gonadal, thyroid, adrenal and growth hormone axis, differentially between animals and humans, as well as in regulating immune function. Beyond these roles, leptin plays a pivotal role in significantly affecting bone health by promoting bone formation and regulating bone metabolism both directly and indirectly through its neuroendocrine actions. The diverse actions of leptin are particularly notable in leptin-deficient animal models and in conditions characterized by low circulating leptin levels, such as lipodystrophies and relative energy deficiency. Conversely, the effectiveness of leptin is attenuated in leptin-sufficient states, such as obesity and other high-adiposity conditions associated with hyperleptinemia and leptin tolerance. This review attempts to consolidate 30 years of leptin research with an emphasis on its physiology and pathophysiology in humans, including its promising therapeutic potential. We discuss preclinical and human studies describing the pathophysiology of energy deficiency across organ systems and the significant role of leptin in regulating neuroendocrine, immune, reproductive and bone health. We finally present past proof of concept clinical trials of leptin administration in leptin-deficient subjects that have demonstrated positive neuroendocrine, reproductive, and bone health outcomes, setting the stage for future phase IIb and III randomized clinical trials in these conditions.

Label-free long-term measurements of adipocyte differentiation from patient-driven fibroblasts and quantitative analyses of in situ lipid droplet generation

The visualization and tracking of adipocytes and their lipid droplets (LDs) during differentiation are pivotal in developmental biology and regenerative medicine studies. Traditional staining or labeling methods, however, pose significant challenges due to their labor-intensive sample preparation, potential disruption of intrinsic cellular physiology, and limited observation timeframe. This study introduces a novel method for long-term visualization and quantification of biophysical parameters of LDs in unlabeled adipocytes, utilizing the refractive index (RI) distributions of LDs and cells. We employ low-coherence holotomography (HT) to systematically investigate and quantitatively analyze the 42-day redifferentiation process of fat cells into adipocytes. This technique yields three-dimensional, high-resolution refractive tomograms of adipocytes, enabling precise segmentation of LDs based on their elevated RI values. Subsequent automated analysis quantifies the mean concentration, volume, projected area, and dry mass of individual LDs, revealing a gradual increase corresponding with adipocyte maturation. Our findings demonstrate that HT is a potent tool for non-invasively monitoring live adipocyte differentiation and analyzing LD accumulation. This study, therefore, offers valuable insights into adipogenesis and lipid research, establishing HT and image-based analysis as a promising approach in these fields.

sEV-mediated lipid droplets transferred from bone marrow adipocytes promote ferroptosis and impair osteoblast function

Osteoporosis is linked to increased bone marrow adipocyte (BMAd) proliferation, which displaces bone-forming cells and alters the local environment. The impact of BMAd lipid droplets on bone health and osteoblast function remains unclear. This study investigates the interplay between BMAd-derived lipid droplets and osteoblast functionality, focusing on ferroptosis pathways. Osteoblast cultures were treated with conditioned media from adipocytes to simulate in vivo conditions. High-throughput mRNA sequencing and Western blot analysis were used to profile changes in gene expression and protein levels related to ferroptosis, oxidative phosphorylation, and osteogenic markers. Cellular assays assessed the direct impact of lipid droplets on osteoblast activity. Results showed that osteoblasts exposed to adipocyte-conditioned media had increased intracellular lipid droplet accumulation, upregulation of ferroptosis-related genes and proteins, and downregulation of oxidative phosphorylation and osteoblast differentiation markers. Treatment with ferroptosis inhibitors reversed the detrimental effects on osteoblasts, indicating the functional relevance of this pathway in osteoporosis. BMAd-derived lipid droplets contribute to osteoblast dysfunction through ferroptosis induction. Inhibiting ferroptosis could preserve osteoblast function and combat osteoporosis-related bone issues, suggesting that modulating lipid metabolism and redox balance in bone cells may be promising for future treatments.

Bone health in adults with obesity before and after interventions to promote weight loss

Obesity and its associated comorbidities constitute a serious and growing public health burden. Fractures affect a substantial proportion of people with obesity and result from reduced bone strength relative to increased mechanical loading, together with an increased risk of falls. Factors contributing to fractures in people with obesity include adverse effects of adipose tissue on bone and muscle and, in many people, the coexistence of type 2 diabetes. Strategies to reduce weight include calorie-restricted diets, exercise, bariatric surgery, and pharmacological interventions with GLP-1 receptor agonists. However, although weight loss in people with obesity has many health benefits, it can also have adverse skeletal effects, with increased bone loss and fracture risk. Priorities for future research include the development of effective approaches to reduce fracture risk in people with obesity and the investigation of the effects of GLP-1 receptor agonists on bone loss resulting from weight reduction.

Secreted protein TNA: a promising biomarker for understanding the adipose-bone axis and its impact on bone metabolism

BACKGROUND

Osteoporosis (OP) is a systemic bone disease characterized by reduced bone mass and deterioration of bone microstructure, leading to increased bone fragility. Platelets can take up and release cytokines, and a high platelet count has been associated with low bone density. Obesity is strongly associated with OP, and adipose tissue can influence platelet function by secreting adipokines. However, the biological relationship between these factors remains unclear.

METHODS

We conducted differential analysis to identify OP platelet-related plasma proteins. And, making comprehensive analysis, including functional enrichment, protein-protein interaction network analysis, and Friends analysis. The key protein, Tetranectin (TNA/CLEC3B), was identified through screening. Then, we analyzed TNA's potential roles in osteogenic and adipogenic differentiation using multiple RNA-seq data sets and validated its effect on osteoclast differentiation and bone resorption function through in vitro experiments.

RESULTS

Six OP-platelet-related proteins were identified via differential analysis. Then, we screened the key protein TNA, which was found to be highly expressed in adipose tissue. RNA-seq data suggested that TNA may promote early osteoblast differentiation. In vitro experiments showed that knockdown of TNA expression significantly increased the expression of osteoclast markers, thereby promoting osteoclast differentiation and bone resorption.

CONCLUSIONS

We identified TNA as a secreted protein that inhibits osteoclast differentiation and bone resorption. While, it potentially promoted early osteoblast differentiation from bioinformatic results. TNA may play a role in bone metabolism through the adipose-bone axis.

Bridging the Gap: A narrative review of osteoporosis disability, adipokines, and the role of AI in postmenopausal women

Osteoporosis is a global health concern characterized by reduced bone density and compromised bone quality, resulting in an increased risk of fractures, particularly in postmenopausal women. The assessment of bone mineral density (BMD) plays a pivotal role in diagnosing osteoporosis, as it accounts for approximately 70% of overall bone strength. The World Health Organization (WHO) has endorsed BMD measurement as a reliable method for diagnosing this condition. In Pakistan, the incidence of bone fractures is on the rise, largely attributable to an aging population and a range of contributing factors. Understanding the global and local prevalence of osteoporosis, its impact on morbidity and mortality, and the contributing factors is vital for developing effective preventive and therapeutic strategies. The role of adipokines, including chemerin, vaspin, and omentin-1, in bone metabolism is an emerging area of investigation. These adipokines play diverse roles in physiology, ranging from inflammation and metabolic regulation to cardiovascular health. Understanding their potential impact on bone health is a topic of ongoing research. The intricate relationship between bone density, bone quality, and overall bone strength is central to understanding the diagnosis and management of osteoporosis. Current innovation in machine learning and predictive model can bring revolution in the field of bone health and osteoporosis. Early identification of people with osteoporosis or risk of fracture through machine learning can prevent disability and improve the quality of life.

FAM19A5 in vascular aging and osteoporosis: Mechanisms and the "calcification paradox"

Aging induces a progressive decline in the vasculature's structure and function. Vascular aging is a determinant factor for vascular ailments in the elderly. FAM19A5, a recently identified adipokine, has demonstrated involvement in multiple vascular aging-related pathologies, including atherosclerosis, cardio-cerebral vascular diseases and cognitive deficits. This review summarizes the current understanding of FAM19A5' role and explores its putative regulatory mechanisms in various aging-related disorders, including cardiovascular diseases (CVDs), metabolic diseases, neurodegenerative diseases and malignancies. Importantly, we provide novel insights into the underlying therapeutic value of FAM19A5 in osteoporosis. Finally, we outline future perspectives on the diagnostic and therapeutic potential of FAM19A5 in vascular aging-related diseases.

Glucagon-like Peptide-1 Receptor Agonists and Diabetic Osteopathy: Another Positive Effect of Incretines? A 12 Months Longitudinal Study

Diabetic osteopathy is a frequent complication in patients with type 2 diabetes mellitus (T2DM). The association between T2DM and increased fracture risk has led to study the impact of new antidiabetic drugs on bone metabolism. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetic drugs which have many pleiotropic properties. The relationship between GLP-1RAs and bone is very complex: while in vitro and animal studies have demonstrated a protective effect on bone, human studies are scarce. We led a 12 months longitudinal study evaluating bone changes in 65 patients withT2DM for whom a therapy with GLP-1RAs had been planned. Fifty-four T2DM patients completed the 12-month study period; of them, 30 had been treated with weekly dulaglutide and 24 with weekly semaglutide. One-year therapy with GLP-1RAs resulted in a significant reduction in weight and BMI. Bone mineral density (BMD), bone metabolism, trabecular bone score (TBS), adiponectin, and myostatin were evaluated before and after 12 months of GLP-1RAs therapy. After 12 months of therapy bone turnover markers and adiponectin showed a significant increase, while myostatin values showed a modest but significant reduction. BMD-LS by DXA presented a significant reduction while the reduction in BMD-LS by REMS was not significant and TBS values showed a marginal increase. Both DXA and REMS techniques showed a modest but significant reduction in femoral BMD. In conclusion, the use of GLP-1RAs for 12 months preserves bone quality and reactivates bone turnover. Further studies are needed to confirm whether GLP-1RAs could represent a useful therapeutic option for patients with T2DM and osteoporosis.

Femoral nailing associated with bone marrow emboli in pigs induced a specific increase in blood IL-6 and broad inflammatory responses in the heart and lungs

Introduction

Bone marrow embolization may complicate orthopedic surgery, potentially causing fat embolism syndrome. The inflammatory potential of bone marrow emboli is unclear. We aimed to investigate the inflammatory response to femoral intramedullary nailing, specifically the systemic inflammatory effects in plasma, and local tissue responses. Additionally, the plasma response was compared to that following intravenous injection of autologous bone marrow.

Methods

Twelve pigs underwent femoral nailing (previously shown to have fat emboli in lung and heart), four received intravenous bone marrow, and four served as sham controls. Blood samples were collected hourly and tissue samples postmortem. Additionally, we incubated bone marrow and blood, separately and in combination, from six pigs in vitro. Complement activation was detected by C3a and the terminal C5b-9 complement complex (TCC), and the cytokines TNF, IL-1β, IL-6 and IL-10 as well as the thrombin-antithrombin complexes (TAT) were all measured using enzyme-immunoassays.

Results

After nailing, plasma IL-6 rose 21-fold, compared to a 4-fold rise in sham (p=0.0004). No plasma differences in the rest of the inflammatory markers were noted across groups. However, nailing yielded 2-3-times higher C3a, TCC, TNF, IL-1β and IL-10 in lung tissue compared to sham (p<0.0001-0.03). Similarly, heart tissue exhibited 2-times higher TCC and IL-1β compared to sham (p<0.0001-0.03). Intravenous bone marrow yielded 8-times higher TAT than sham at 30 minutes (p<0.0001). In vitro, incubation of bone marrow for four hours resulted in 95-times higher IL-6 compared to whole blood (p=0.03).

Discussion

A selective increase in plasma IL-6 was observed following femoral nailing, whereas lung and heart tissues revealed a broad local inflammatory response not reflected systemically. In vitro experiments may imply bone marrow to be the primary IL-6 source.

PCLAF induces bone marrow adipocyte senescence and contributes to skeletal aging

Bone marrow adipocytes (BMAds) affect bone homeostasis, but the mechanism remains unclear. Here, we showed that exercise inhibited PCNA clamp-associated factor (PCLAF) secretion from the bone marrow macrophages to inhibit BMAds senescence and thus alleviated skeletal aging. The genetic deletion of PCLAF in macrophages inhibited BMAds senescence and delayed skeletal aging. In contrast, the transplantation of PCLAF-mediated senescent BMAds into the bone marrow of healthy mice suppressed bone turnover. Mechanistically, PCLAF bound to the ADGRL2 receptor to inhibit AKT/mTOR signaling that triggered BMAds senescence and subsequently spread senescence among osteogenic and osteoclastic cells. Of note, we developed a PCLAF-neutralizing antibody and showed its therapeutic effects on skeletal health in old mice. Together, these findings identify PCLAF as an inducer of BMAds senescence and provide a promising way to treat age-related osteoporosis.

Fatty infiltration in the musculoskeletal system: pathological mechanisms and clinical implications

Fatty infiltration denotes the anomalous accrual of adipocytes in non-adipose tissue, thereby generating toxic substances with the capacity to impede the ordinary physiological functions of various organs. With aging, the musculoskeletal system undergoes pronounced degenerative alterations, prompting heightened scrutiny regarding the contributory role of fatty infiltration in its pathophysiology. Several studies have demonstrated that fatty infiltration affects the normal metabolism of the musculoskeletal system, leading to substantial tissue damage. Nevertheless, a definitive and universally accepted generalization concerning the comprehensive effects of fatty infiltration on the musculoskeletal system remains elusive. As a result, this review summarizes the characteristics of different types of adipose tissue, the pathological mechanisms associated with fatty infiltration in bone, muscle, and the entirety of the musculoskeletal system, examines relevant clinical diseases, and explores potential therapeutic modalities. This review is intended to give researchers a better understanding of fatty infiltration and to contribute new ideas to the prevention and treatment of clinical musculoskeletal diseases.

Saturated fatty acids stimulate cytokine production in tanycytes via the PP2Ac-dependent signaling pathway

The hypothalamic tanycytes are crucial for free fatty acids (FFAs) detection, storage, and transport within the central nervous system. They have been shown to effectively respond to fluctuations in circulating FFAs, thereby regulating energy homeostasis. However, the precise molecular mechanisms by which tanycytes modulate lipid utilization remain unclear. Here, we report that the catalytic subunit of protein phosphatase 2 A (PP2Ac), a serine/threonine phosphatase, is expressed in tanycytes and its accumulation and activation occur in response to high-fat diet consumption. In vitro, tanycytic PP2Ac responds to palmitic acid (PA) exposure and accumulates and is activated at an early stage in an AMPK-dependent manner. Furthermore, activated PP2Ac boosts hypoxia-inducible factor-1α (HIF-1α) accumulation, resulting in upregulation of an array of cytokines. Pretreatment with a PP2Ac inhibitor, LB100, prevented the PA-induced elevation of vascular endothelial growth factor (VEGF), fibroblast growth factor 1 (FGF1), hepatocyte growth factor (HGF), and dipeptidyl peptidase IV (DPPIV or CD26). Our results disclose a mechanism of lipid metabolism in tanycytes that involves the activation of PP2Ac and highlight the physiological significance of PP2Ac in hypothalamic tanycytes in response to overnutrition and efficacious treatment of obesity.

Bone marrow adipocytes and lung cancer bone metastasis: unraveling the role of adipokines in the tumor microenvironment

Bone is a common site of metastasis for lung cancer. The "seed and soil" hypothesis suggests that the bone marrow microenvironment ("soil") may provide a conducive survival environment for metastasizing tumor cells ("seeds"). The bone marrow microenvironment, comprising a complex array of cells, includes bone marrow adipocytes (BMAs), which constitute about 70% of the adult bone marrow volume and may play a significant role in tumor bone metastasis. BMAs can directly provide energy for tumor cells, promoting their proliferation and migration. Furthermore, BMAs participate in the tumor microenvironment's osteogenesis regulation, osteoclast(OC) regulation, and immune response through the secretion of adipokines, cytokines, and inflammatory factors. However, the precise mechanisms of BMAs in lung cancer bone metastasis remain largely unclear. This review primarily explores the role of BMAs and their secreted adipokines (leptin, adiponectin, Nesfatin-1, Resistin, chemerin, visfatin) in lung cancer bone metastasis, aiming to provide new insights into the mechanisms and clinical treatment of lung cancer bone metastasis.

Anti-osteoporotic treatments in the era of non-alcoholic fatty liver disease: friend or foe

Over the last years non-alcoholic fatty liver disease (NAFLD) has grown into the most common chronic liver disease globally, affecting 17-38% of the general population and 50-75% of patients with obesity and/or type 2 diabetes mellitus (T2DM). NAFLD encompasses a spectrum of chronic liver diseases, ranging from simple steatosis (non-alcoholic fatty liver, NAFL) and non-alcoholic steatohepatitis (NASH; or metabolic dysfunction-associated steatohepatitis, MASH) to fibrosis and cirrhosis with liver failure or/and hepatocellular carcinoma. Due to its increasing prevalence and associated morbidity and mortality, the disease-related and broader socioeconomic burden of NAFLD is substantial. Of note, currently there is no globally approved pharmacotherapy for NAFLD. Similar to NAFLD, osteoporosis constitutes also a silent disease, until an osteoporotic fracture occurs, which poses a markedly significant disease and socioeconomic burden. Increasing emerging data have recently highlighted links between NAFLD and osteoporosis, linking the pathogenesis of NAFLD with the process of bone remodeling. However, clinical studies are still limited demonstrating this associative relationship, while more evidence is needed towards discovering potential causative links. Since these two chronic diseases frequently co-exist, there are data suggesting that anti-osteoporosis treatments may affect NAFLD progression by impacting on its pathogenetic mechanisms. In the present review, we present on overview of the current understanding of the liver-bone cross talk and summarize the experimental and clinical evidence correlating NAFLD and osteoporosis, focusing on the possible effects of anti-osteoporotic drugs on NAFLD.

Interaction between Selected Adipokines and Musculoskeletal and Cardiovascular Systems: A Review of Current Knowledge

Adipokines are substances secreted by adipose tissue that are receiving increasing attention. The approach to adipose tissue has changed in recent years, and it is no longer looked at as just a storage organ but its secretion and how it influences systems in the human body are also looked at. The role of adipokine seems crucial in developing future therapies for pathologies of selected systems. In this study, we look at selected adipokines, leptin, adiponectin, chemerin, resistin, omentin-1, nesfatin, irisin-1, visfatin, apelin, vaspin, heparin-binding EGF-like growth factor (HB-EGF), and TGF-β2, and how they affect systems in the human body related to physical activity such as the musculoskeletal and cardiovascular systems.

Correlation between bone mineral density and sarcopenia in US adults: a population-based study

INTRODUCTION

In the aging process of the body, in addition to changes in fat and muscle content, there is also bone loss, implying the possibility of a strong muscle-bone-lipid link. In this study, we initially investigated the relationship between lumbar BMD and low muscle mass and the relationship between "muscle-bone-lipid."

METHODS

The datasets from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in a cross-sectional investigation. BMD and appendicular skeletal muscle (ASM) were measured by dual-energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by body mass index (BMI) as a marker of sarcopenia. Weighted multivariate regression and logistic regression analysis were used to explore the independent relationship between lumbar BMD and sarcopenia. Fitted smoothing curves and threshold effect analysis were used to describe the nonlinear relationship.

RESULT

In 8386 participants with ages 20-59 years, there was a negative association between lumbar BMD and sarcopenia. In the fully adjusted model, the risk of developing sarcopenia decreased by 93% for each 1-unit increase in lumbar BMD (OR = 0.07, 95%CI 0.03-0.20). The risk of sarcopenia was 58% lower in participants in the highest quartile of lumbar BMD than in those in the lowest quartile (OR = 0.42, 95%CI 0.27-0.64). This negative association was more pronounced in the population of women with BMI ≥ 25.

CONCLUSION

Our findings suggest that lumbar BMD is negatively associated with sarcopenia in US adults. The dynamic balance between "muscle-bone-lipid" is likely to be related to the pathogenesis of bone loss.

Assessment of osteoporosis in patients with type 2 diabetes mellitus: A study from the central region of Saudi Arabia

OBJECTIVES

To understand the impact of diabetes on bone mineral density and whether it increases the likelihood of osteoporosis.

METHODS

This study was performed on 327 Saudis (aged >40 years) who were screened for osteoporosis and diabetes mellitus (DM). The levels of osteoporosis were determined by an estimation of Bone mineral density (BMD) using a DEXA scan examination. The data on BMD from diabetic subjects were compared with healthy nondiabetic controls.

RESULTS

Out of 327 enrolled subjects, 38 (11.6%) were found to be osteoporotic, whereas 138 (42.2%) had DM. The data showed that the number of patients with osteoporosis in the DM group was 14 (36.8%), significantly lower than in nondiabetic patients, 21 (55.2%) (p=0.0015). Notably, the data showed no significant difference in the mean BMD of the femur in patients with DM (0.926 g/cm2) and non-diabetes (0.936 g/cm2) (p=0.280; T-score p=0.4746). The mean BMD levels in the spine of the DM study group (1.049 g/cm2) were significantly higher when compared with nondiabetic healthy controls (0.990 g/cm2) (p=0.0031).

CONCLUSION

Patients with diabetes had higher lumbar BMD than nondiabetics, although femoral BMD was similar. Patients with diabetes have a lower osteoporosis risk than nondiabetics.