Association between serum osteocalcin and body mass index: a systematic review and meta-analysis

Osteocalcin is inversely associated with worse adipose tissue distribution and cardiovascular risk in autoimmune diabetes

BACKGROUND

Osteocalcin (OCN), whose release is impaired in diabetes, is suggested to regulate the adipose tissue (AT), being potentially associated with Cardiovascular risk (CVR). We aimed at evaluating whether OCN serum levels are associated with AT health and CVR in a primary CV prevention population with AD.

METHODS

Body mass composition was assessed in sixty-two people with AD.Serum levels of OCN, adipokines and markers of endothelial dysfunction were measured. Regression models were used to test the association of OCN with markers of AT, endothelial dysfunction and CVR categories as determined by the Steno Type 1 Risk Engine (ST1RE) score.

RESULTS

OCN was inversely associated with upper body fat deposition index (UBDFI) (Adj β coefficient -0.484, p value = 0.001). People in medium/high CV risk categories had higher UBFDI and lower OCN, while biomarkers of endothelial dysfunction were not different across CVR classes. A logistic binary regression for ST1RE score showed significant association of OCN with medium/high CVR category: OR [95 % CI for 1 SD increase: 0.541 [0.264--1.108], p = 0.093].

CONCLUSION

OCN is inversely associated with unhealthy AT, supporting the protective role of OCN in AT. Moreover, lower OCN levels are associated with increased CVR in AD population.

Associations among body condition score, body weight, and serum biochemistry in dairy cows

Body condition score and BW yield insights into body tissue reserves and diet, and serum biochemical measures reflect the metabolic status of cows. Associations between body composition measures and biochemistry are unclear and investigation may reveal important information on the metabolic and physiological status of cattle with varying levels of labile tissue reserves. Cohorts of 739 nonlactating, late-pregnancy, dry cows (26.9 d prepartum, SD = 12.4) and 690 peak-milk cows (58.0 DIM, SD = 14.5) were selected by stratified (parity: 1, 2, 3, >3) random sampling from 30 farms (15 pasture, 15 TMR) in this cross-sectional study. A single serum, BCS (1-5 scale), BW, and milk-production datum was collected per cow, per cohort between November 2022 and July 2023. Eleven analytes were collected, analyzed, and standardized within group (cohort/breed per farm). Mixed linear models for BCS and BW were specified, with the random effect of group. A 6-point, unordered, categorical body-group classification that combined BCS (greater, equal to, or less than group median; as high, median, or low BCS) and BW (greater or less than group median; as high or low BW) was analyzed by polytomous logistic regression. Effect sizes are listed for a 1 SD increase in the specified analyte, keeping other covariables at their mean value. Dry BCS was positively associated with albumin (0.075 BCS ± 0.014 SE), urea (0.038 BCS ± 0.014 SE), and glucose (0.052 BCS ± 0.014 SE), and negatively with the interaction between cholesterol and days precalving. Dry BW positively associated with albumin (11.03 kg ± 2.48 SE) and negatively with cholesterol (-8.47 kg ± 2.57 SE). Peak-milk BCS was positively associated with albumin (0.47 BCS ± 0.015 SE), BHB (0.048 BCS ± 0.015 SE), and glucose (0.051 BCS ± 0.015 SE). Peak-milk BW was positively associated with albumin (6.94 kg ± 2.35 SE) and negatively with Ca (-7.02 kg ± 2.33 SE). Increasing BW and decreasing BCS was associated with increasing parity, except in dry second-parity cows that had low BCS. The dry polytomous model associated a 1 SD increase in albumin with a 4.89% ± 1.56 SE decreased risk of being low BCS/low BW and 5.87% ± 1.46 SE increased risk of high BCS/high BW. Risk change associated with 1 SD of glucose was -5.61% ± 1.58 SE for low BCS/high BW and 3.17% ± 1.58 SE for high BCS/high BW. For the peak-milk cohort, change in risk was associated with albumin for low BCS/low BW -3.67% ± 1.56 SE, low BCS/high BW -3.22% ± 1.53 SE. Risk change with 1 SD of BHB was -3.36% ± 1.47 SE for median BCS/low BW, 2.86% ± 1.44 SE for high BCS/low BW, and 2.69% ± 1.37 SE for high BCS/high BW. Risk of low BCS/low BW was greatest in second-parity cows, and high BCS/high BW was greatest in dry cows with greater than third parity and third-parity cows in peak milk. There were no interactions between parity and analytes. Albumin was consistently associated with BCS and BW, potentially reflecting innate differences in protein metabolism of cows.

The bone-heart axis in the pathogenesis of cardiovascular diseases: A narrative review

Cardiovascular diseases (CVDs) cause about 30% of deaths worldwide, increasing social and economic burden in our societies. Although the treatment of the canonical cardiovascular risk factors has reduced the impact of CVDs on morbidity and mortality in the past few years, they continue to represent a major health problem. The definition of the biological properties of the bone-heart axis has led to new insights in the pathogenesis of CVDs; hence, the aim of this review is to try to elucidate the role of this axis on the susceptibility to CVDs. There is evidence that the bone interacts with extra-skeletal organs, including the cardiovascular system, through its endocrine functions. Clinical and experimental data strongly indicate that the interplay between the bone and the cardiovascular system represents a future tool for the prevention, diagnosis and treatment of CVDs. The identification of these non-canonical cardiovascular risk factors could prompt pharmacological research towards new target therapy aimed at precision medicine.

Osteokines in Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

To critically summarize evidence on the potential role of osteokines in the pathogenesis and progression of nonalcoholic fatty liver disease (NAFLD).

RECENT FINDINGS

There are emerging data supporting that certain osteokines, which are specific bone-derived proteins, may beneficially or adversely affect hepatic metabolism, and their alterations in the setting of osteoporosis or other bone metabolic diseases may possibly contribute to the development and progression of NAFLD. There is evidence showing a potential bidirectional association between NAFLD and bone metabolism, which may imply the existence of a liver-bone axis. In this regard, osteocalcin, osteoprotegerin, bone morphogenic protein 4 (BMP4) and BMP6 appear to have a positive impact on the liver, thus possibly alleviating NAFLD, whereas osteopontin, receptor activator of nuclear factor kappa Β ligand (RANKL), sclerostin, periostin, BMP8B, and fibroblast growth factor 23 (FGF23) appear to have a negative impact on the liver, thus possibly exacerbating NAFLD. The potential implication of osteokines in NAFLD warrants further animal and clinical research in the field that may possibly result in novel therapeutic targets for NAFLD in the future.

The role of bone in energy metabolism: A focus on osteocalcin

Understanding the mechanisms involved in whole body glucose regulation is key for the discovery of new treatments for type 2 diabetes (T2D). Historically, glucose regulation was largely focused on responses to insulin and glucagon. Impacts of incretin-based therapies, and importance of muscle mass, are also highly relevant. Recently, bone was recognized as an endocrine organ, with several bone proteins, known as osteokines, implicated in glucose metabolism through their effects on the liver, skeletal muscle, and adipose tissue. Research efforts mostly focused on osteocalcin (OC) as a leading example. This review will provide an overview on this role of bone by discussing bone turnover markers (BTMs), the receptor activator of nuclear factor kB ligand (RANKL), osteoprotegerin (OPG), sclerostin (SCL) and lipocalin 2 (LCN2), with a focus on OC. Since 2007, some, but not all, research using mostly OC genetically modified animal models suggested undercarboxylated (uc) OC acts as a hormone involved in energy metabolism. Most data generated from in vivo, ex vivo and in vitro models, indicate that exogenous ucOC administration improves whole-body and skeletal muscle glucose metabolism. Although data in humans are generally supportive, findings are often discordant likely due to methodological differences and observational nature of that research. Overall, evidence supports the concept that bone-derived factors are involved in energy metabolism, some having beneficial effects (ucOC, OPG) others negative (RANKL, SCL), with the role of some (LCN2, other BTMs) remaining unclear. Whether the effect of osteokines on glucose regulation is clinically significant and of therapeutic value for people with insulin resistance and T2D remains to be confirmed.

Role of osteokines in atherosclerosis

Despite their diverse physiologies and roles, the heart, skeletal muscles, and smooth muscles all derive from a common embryonic source as bones. Moreover, bone tissue, skeletal and smooth muscles, and the heart share conserved signaling pathways. The maintenance of skeletal health is precisely regulated by osteocytes, osteoblasts, and osteoclasts through coordinated secretion of bone-derived factors known as osteokines. Increasing evidence suggests the involvement of osteokines in regulating atherosclerotic vascular disease. Therefore, this review aims to examine the evidence for the role of osteokines in atherosclerosis development and progression comprehensively. Specifically discussed are extensively studied osteokines in atherosclerosis such as osteocalcin, osteopontin, osteoprotegerin, and fibroblast growth factor 23. Additionally, we highlighted the effects of exercise on modulating these key regulators derived from bone tissue metabolism. We believe that gaining an enhanced understanding of how osteocalcin contributes to the process of atherosclerosis will enable us to develop targeted and comprehensive therapeutic strategies against diseases associated with its progression.

Fetal femur length and risk of diabetes in adolescence: a prospective cohort study

BACKGROUND

Diabetes is more apparent in adulthood but may be dormant in childhood and originates during early fetal development. In fetal biometry, femur length (FL) is crucial for assessing fetal growth and development. This study aimed to assess potential associations between fetal femur growth and prediabetic biomarkers in Bangladeshi children.

METHODS

A cohort study embedded in a population-based maternal food and micronutrient supplementation (MINIMat) trial was conducted in Matlab, Bangladesh. The children in the cohort were followed up until 15 years of age. In the original trial, pregnancy was confirmed by ultrasound before 13 gestational weeks (GWs). Afterward, ultrasound assessments were performed at 14, 19, and 30 GWs. FL was measured from one end to the other, capturing a complete femoral image. The FL was standardized by GW, and a z-score was calculated. FBG and HbA1c levels were determined in plasma and whole blood, and the triglyceride-glucose index, a biomarker of insulin resistance, was calculated as Ln [fasting triglycerides (mg/dl) × fasting glucose (mg/dl)/2]. Multivariable linear regression analysis using a generalized linear model was performed to estimate the effects of FL at 14, 19 and 30 GWs on prediabetic biomarkers at 9 and 15 years of age. Maternal micronutrient and food supplementation group, parity, child sex, and BMI at 9 years or 15 years were included as covariates.

RESULTS

A total of 1.2% (6/515) of the participants had impaired fasting glucose during preadolescence, which increased to 3.5% (15/433) during adolescence. At 9 years, 6.3% (32/508) of the participants had elevated HbA1c%, which increased to 28% (120/431) at 15 years. Additionally, the TyG index increased from 9.5% (49/515) (during preadolescence) to 13% (56/433) (during adolescence). A one standard deviation decrease in FL at 14 and 19 GWs was associated with increased FBG (β = - 0.44 [- 0.88, - 0.004], P = 0.048; β = - 0.59 [- 1.12, - 0.05], P = 0.031) and HbA1c (β = - 0.01; [- 0.03, -0.005], P = 0.007; β = - 0.01 [- 0.03, - 0.003], P = 0.018) levels at 15 years. FL was not associated with diabetic biomarkers at 9 years.

CONCLUSION

Mid-trimester impaired femur growth may be associated with elevated prediabetic biomarkers in Bangladeshi adolescents.

Osteocalcin: Beyond Bones

Apart from basic roles such as supporting the body, protecting internal organs, and storing calcium, the skeletal system also performs hormonal functions. In recent years, several reports have been published on proteins secreted by bones and their impact on the homeostasis of the entire body. These proteins include fibroblast growth factor 23, sclerostin, lipocalin 2, and osteocalcin. Osteocalcin, the most abundant non-collagenous protein in bone tissue, is routinely measured as a clinical marker for diagnosing bone metabolism disorders. Its molecule undergoes numerous transformations, with decarboxylation being the critical process. Decarboxylation occurs in the acidic environment typical of bone resorption, facilitating the release of the molecule into the bloodstream and enabling its hormonal action. Decarboxylated osteocalcin promotes insulin secretion and stimulates the proliferation of pancreatic islet β-cells. It also plays a role in reducing the accumulation of visceral fat and decreasing fat storage in the liver. Furthermore, decarboxylated osteocalcin levels are inversely correlated with fasting serum glucose levels, total body fat, visceral fat area, and body mass index. Apart from its role in energy metabolism, osteocalcin affects testosterone production and the synthesis of glucagon-like peptide-1. It is also actively involved in muscle-bone crosstalk and influences cognitive function.

Efficacy and Possible Mechanisms of Astragali Radix and its Ingredients in Animal Models of Osteoporosis: A Preclinical Review and Metaanalysis

BACKGROUND

Astragali Radix (AR) has a long history as a traditional Chinese medicine for anti-osteoporosis (OP) treatment. The aim of the study was to explore the effect and optimal regimens of AR and its main ingredients (IAR) in OP treatment.

METHODS

Eligible animal studies were searched in seven databases (PubMed, Web of Science, MEDLINE, SciELO Citation Index, Cochrane Library, China National Knowledge Infrastructure and Wanfang). The primary outcomes were bone metabolic indices. The secondary outcome measure was the anti-OP mechanism of IAR.

RESULTS

21 studies were enrolled in the study. The primary findings of the present article illustrated that IAR could significantly increase the bone mineral density (BMD), bone volume over the total volume, trabecular number, trabecular thickness, bone maximum load and serum calcium, while trabecular separation and serum C-terminal telopeptide of type 1 collagen were remarkably decreased (P < 0.05). In subgroup analysis, the BMD in the long treatment group (≥ 10 weeks) showed better effect size than the short treatment group (< 10 weeks) (P < 0.05). Modeling methods and animal sex were factors affecting serum alkaline phosphatase and osteocalcin levels.

CONCLUSION

The findings suggest the possibility of developing IAR as a drug for the treatment of OP. IAR with longer treatment time may achieve better effects regardless of animal strain and age.

Association between insulin resistance related indicators with the prognosis of patients with colorectal cancer

BACKGROUND

The progression of colorectal cancer (CRC) has been linked to metabolism alteration. Because insulin resistance (IR) is the basic mechanism of metabolism alteration, IR related indicators are considered to be associated with prognostic of CRC. In this study, we compared the prognostic values of common IR related indicators for CRC and selected the best one. Moreover, we explored the association between that indicator and CRC prognosis and possible interactive covariates.

METHODS

Medical records of patients with CRC (n = 1765) were retrieved from the Investigation on Nutrition Status and Clinical Outcome of Common Cancers (INSCOC) study. We compared the prognostic values of IR related indicators and select the best one using concordance index (C-index) and area under curve (AUC). Using Cox proportional hazard regression models, we evaluated the association between that indicator and CRC prognosis. Interaction tests were performed to evaluate possible interactions among covariates and the IR related indicator.

RESULTS

Results of C-index and AUC indicated that the ratio of low-density lipoprotein-to-high-density lipoprotein (LHR) showed the highest ability to predict the prognosis of patients with CRC. LHR independently predicted CRC prognosis [hazard ratio (HR) = 1.14; 95 % confidence interval (CI) = 1.05-1.22; P = 0.001]. The interactions between LHR, and age (<65 vs. ≥65; P for interaction = 0.001) or neutrocyte-to-lymphocyte ratio (NLR) (<3 vs. ≥3; P for interaction = 0.055) were also observed.

CONCLUSION

LHR was found to be the best IR related indicators to predict prognosis of CRC, and it was negatively correlated with the prognosis of patients with CRC. NLR and aging might interact with LHR.

Targeting aging with the healthy skeletal system: The endocrine role of bone

Aging is an inevitable biological process, and longevity may be related to bone health. Maintaining strong bone health can extend one's lifespan, but the exact mechanism is unclear. Bone and extraosseous organs, including the heart and brain, have complex and precise communication mechanisms. In addition to its load bearing capacity, the skeletal system secretes cytokines, which play a role in bone regulation of extraosseous organs. FGF23, OCN, and LCN2 are three representative bone-derived cytokines involved in energy metabolism, endocrine homeostasis and systemic chronic inflammation levels. Today, advanced research methods provide new understandings of bone as a crucial endocrine organ. For example, gene editing technology enables bone-specific conditional gene knockout models, which allows the study of bone-derived cytokines to be more precise. We systematically evaluated the various effects of bone-derived cytokines on extraosseous organs and their possible antiaging mechanism. Targeting aging with the current knowledge of the healthy skeletal system is a potential therapeutic strategy. Therefore, we present a comprehensive review that summarizes the current knowledge and provides insights for futures studies.

Sex Differences and Positive Dose-Response Relationships between Serum Osteocalcin Levels and Low Muscle Strength

INTRODUCTION

Impaired handgrip strength is an indication for sarcopenia and frailty screening, and is associated with increased osteoporotic risks and all-cause mortality. Osteocalcin, secreted by osteoblasts, is a versatile factor that participates in bone turnover and muscle adaptation. The role of osteocalcin in muscle strength has mainly been discussed in animal models and requires more human data. The study aimed to investigate the association between the serum osteocalcin level and handgrip strength in middle-aged individuals and older adults with diabetes.

METHODS

Adult participants (aged 40 and above, N = 237) with diabetes were enrolled in a medical center in northern Taiwan. Subjects were divided into normal, low muscle mass without dynapenia, dynapenia without low muscle mass, and groups of low muscle mass with dynapenia according to their handgrip strength and muscle mass measurements. Physical performance, including handgrip strength, repeated sit-to-stand tests, walking speed, and short physical performance batteries, was documented. Body composition was measured by bioelectrical impedance analysis.

RESULTS

The median serum osteocalcin level was highest in the dynapenic group without low muscle mass (median [Q1, Q3], 14.1 [11.2, 16.3] ng/mL). Multivariate logistic regression showed that a higher serum osteocalcin level was associated with worse handgrip strength (OR: 3.89, 95% CI: 1.66-9.10) after adjusting for body mass index (adiposity), skeletal muscle mass index (muscle), and medication with dipeptidyl peptidase-4 inhibitor. Further sex stratification revealed a more significant association between serum osteocalcin level and impaired handgrip strength in women but not in men. The female groups showed increases in the risk of impaired handgrip strength: 4.84-fold in the osteocalcin T2 group (11.4 ≤ osteocalcin <15.0 ng/mL) and 4.54-fold in the osteocalcin T3 group (osteocalcin ≥15.0 ng/mL). Moreover, after adjusting for various confounders, 8.41-fold and 8.03-fold increases in the risk of impaired handgrip strength were observed in the osteocalcin T2 group (11.4≤ osteocalcin <15.0 ng/mL) and osteocalcin T3 group (osteocalcin ≥14.5 ng/mL), respectively.

CONCLUSION

Higher serum osteocalcin is associated with increased risks of impaired handgrip strength and impaired physical performance. Dose-dependent associations were found especially in postmenopausal women but not in men.

Serum Osteocalcin, Sclerostin and Lipocalin-2 Levels in Adolescent Boys with Obesity over a 12-Week Sprint Interval Training

The aim of the study was to examine the effects of supervised cycling sprint interval training (SIT) on serum osteocalcin, lipocalin-2 and sclerostin levels, and bone mineral characteristics among obese adolescent boys. Untrained obese adolescent boys aged 13.4 ± 0.3 were assigned to either a 12-week SIT group (3 sessions/week), or a non-exercising control group who continued with their habitual everyday life. Serum osteocalcin, lipocalin-2 and sclerostin concentrations, and bone mineral values were assessed before and after intervention. After 12-week intervention, where 14 boys in both groups ended the study, there were no significant differences in serum osteokine levels between the groups after 12 weeks, while whole body bone mineral content and lower limb bone mineral density increased in the SIT group (p < 0.05). Change in body mass index was negatively correlated with the change in osteocalcin (r = -0.57; p = 0.034), and positively correlated with the change in lipocalin-2 levels (r = 0.57; p = 0.035) in the SIT group. Supervised 12-week SIT intervention improved bone mineral characteristics, but did not change osteocalcin, lipocalin-2 or sclerostin levels in adolescent boys with obesity.

New insight of obesity-associated NAFLD: Dysregulated "crosstalk" between multi-organ and the liver?

Obesity plays a crucial role in the development of non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanism for the pathogenesis of obesity-associated NAFLD remains largely obscure. Although the "multiple hit" theory provides a more accurate explanation of NAFLD pathogenesis, it still cannot fully explain precisely how obesity causes NAFLD. The liver is the key integrator of the body's energy needs, receiving input from multiple metabolically active organs. Thus, recent studies have advocated the "multiple crosstalk" hypothesis, highlighting that obesity-related hepatic steatosis may be the result of dysregulated "crosstalk" among multiple extra-hepatic organs and the liver in obesity. A wide variety of circulating endocrine hormones work together to orchestrate this "crosstalk". Of note, with deepening understanding of the endocrine system, the perception of hormones has gradually risen from the narrow sense (i.e. traditional hormones) to the broad sense of hormones as organokines and exosomes. In this review, we focus on the perspective of organic endocrine hormones (organokines) and molecular endocrine hormones (exosomes), summarizing systematically how the two types of new hormones mediate the dialogue between extra-hepatic organs and liver in the pathogenesis of obesity-related NAFLD.

Association between osteocalcin, a pivotal marker of bone metabolism, and secretory function of islet beta cells and alpha cells in Chinese patients with type 2 diabetes mellitus: an observational study

BACKGROUND

Several recent studies have found that Osteocalcin (OCN), a multifunctional protein secreted exclusively by osteoblasts, is beneficial to glucose metabolism and type 2 diabetes mellitus (T2DM). However, the effects of OCN on islets function especially islet ɑ cells function in patients with type 2 diabetes mellitus characterized by a bi-hormonal disease are still unclear. The purpose of this cross-sectional study was to investigate the relationship between serum OCN and the secretion of islet β cells and ɑ cells in Chinese patients with type 2 diabetes mellitus.

METHODS

204 patients with T2DM were enrolled. Blood glucose (FBG, PBG0.5h, PBG1h, PBG2h, PBG3h), insulin (FINS, INS0.5h, INS1h, INS2h, INS3h), C-peptide (FCP, CP0.5h, CP1h, CP2h, CP3h), and glucagon (GLA0, GLA0.5 h, GLA1h, GLA2h, GLA3h) levels were measured on 0 h, 0.5 h, 1 h, 2 h, and 3 h after a 100 g standard bread meal load. Early postprandial secretion function of islet β cells was calculated as Δcp0.5h = CP0.5-FCP. The patients were divided into low, medium and high groups (T1, T2 and T3) according to tertiles of OCN. Comparison of parameters among three groups was studied. Correlation analysis confirmed the relationship between OCN and pancreatic secretion. Multiple regression analysis showed independent contributors to pancreatic secretion.

MAIN RESULTS

FBG, and PBG2h were the lowest while Δcp0.5h was the highest in the highest tertile group (respectively, p < 0.05). INS3h, area under the curve of insulin (AUCins3h) in T3 Group were significantly lower than T1 Group (respectively, p < 0.05). GLA1h in T3 group was lower than T1 group (p < 0.05), and GLA0.5 h in T3 group was lower than T2 and T1 groups (p < 0.05). Correlation analysis showed OCN was inversely correlated with Homeostatic model of insulin resistance (HOMA-IR), INS3h, AUCins3h (p < 0.05), and was still inversely correlated with FCP, GLA0.5 h, GLA1h, area under the curve of glucagon (AUCgla3h) (respectively, p < 0.05) after adjustment for body mass index (BMI) and alanine aminotransferase (ALT). The multiple regression analysis showed that OCN was independent contributor to Δcp0.5h, GLA0.5h and GLA1h (respectively, p < 0.05).

CONCLUSIONS

Higher serum OCN level is closely related to better blood glucose control, higher insulin sensitivity, increased early-phase insulin secretion of islet β cells and appropriate inhibition of postprandial glucagon secretion of islet ɑ cells in adult patients with type 2 diabetes mellitus.

Consistently Low Levels of Osteocalcin From Late Pregnancy to Postpartum Are Related to Postpartum Abnormal Glucose Metabolism in GDM Patients

OBJECTIVE

Increasing evidence suggests that osteocalcin (OC), a marker of bone formation, plays an important role in glucose homoeostasis. Few studies have investigated the relationship between OC levels in gestational diabetes mellitus (GDM) patients and their postpartum glucose metabolism. This study evaluated the relationship between OC levels in late pregnancy, their longitudinal changes, and postpartum glucose metabolism among GDM patients.

MEASURES

Serum OC was measured in late pregnancy and the postpartum period for 721 GDM patients. All patients underwent a 75-g oral glucose tolerance test (OGTT) at 6-8 weeks postpartum. According to postpartum OGTT outcomes, patients were categorized into abnormal glucose metabolism (AGM) (n=255) and normal glucose tolerance (NGT) groups (n=466). Glucose metabolism-related indices were measured and calculated. Logistic regression analysis and linear mixed-effects model were used to assess the association between OC and postpartum AGM.

RESULTS

In late pregnancy, OC levels were lower in the AGM group than in the NGT group (13.93 ± 6.90 vs 15.33 ± 7.63 ng/ml, P=0.015). After delivery, OC levels increased in both groups. However, OC levels remained lower in the AGM group than in the NGT group (23.48 ± 7.84 vs 25.65 ± 8.37 ng/ml, P=0.001). Higher OC levels in late pregnancy were associated with decreased risk of progressing to postpartum AGM (OR:0.96, 95%CI:0.94-0.99). Linear mixed-effects analysis showed that postpartum AGM patients exhibited consistently lower OC levels than NGT group from late pregnancy to the postpartum period after adjustment for cofactors (β=-1.70, 95% CI: -2.78- -0.62).

CONCLUSIONS

In GDM patients, consistently low levels of OC from late pregnancy to postpartum were associated with increased postpartum AGM risk. The increase in serum OC may act as a protective factor to curb the progression of AGM at postpartum for GDM patients.

Pattern of Adiponectin, Osteocalcin, Irisin, FGF-21, and MCP-1 According to the Body Size Phenotype: Could They Be Markers of Metabolic Health in Mexican-Mestizo Middle-Aged Women?

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), and VAT (r = 0.645; p = 0.0001); FGF-21 with insulin (r = -0.337; p= 0.030) and HOMA-IR (r = -0.341; p = 0.03); and MCP-1 with BMI (r = 0.481; p = 0.0001), VAT (r = 0.497; p = 0.001), insulin (r = 0.298; p= 0.001), and HOMA-IR (r = 0.255; p = 0.004). A multivariate analysis showed that an elevation of OCN (OR 1.4 (_95%CI 1.06-1.81)) and a reduction of adiponectin (OR 0.9 (0.84-0.96)) were associated factors for a metabolic unhealthy phenotype in normal weight participants. Likewise, higher irisin (OR 1.007 (1.003-1.011)) and MCP-1 (1.044 (1.008-1.083)) were risk factors for a metabolic unhealthy phenotype in woman with obesity. OCN, adiponectin, irisin, FGF-21, and MCP-1 are associated with some metabolic parameters such as BMI, HOMA-IR, and VAT, and could be possible biomarkers of an unhealthy metabolic phenotype in middle-aged women.

Associations of Osteocalcin Forms With Metabolic Syndrome and Its Individual Components in Older Men: The Health In Men Study

CONTEXT

The osteoblast-derived polypeptide, osteocalcin (OC), has been associated with lower risk of type 2 diabetes and metabolic syndrome (MetS) in several epidemiological studies. Animal studies have indicated the undercarboxylated form of OC (ucOC) drives its association with metabolic outcomes.

OBJECTIVE

We compared associations of ucOC and carboxylated OC (cOC) with MetS and its components in older men.

METHODS

A cross-sectional analysis of 2575 men aged ≥70 years and older resident in Perth, Western Australia. ucOC was assayed using a hydroxyapatite-binding method, and cOC calculated by subtracting ucOC from total OC. Main outcome measures were MetS and its components.

RESULTS

Both lower serum ucOC and cOC levels, and the proportion of cOC (%cOC) were associated with less favorable metabolic parameters (higher waist circumference, triglyceride, glucose, blood pressure, and lower high-density lipoprotein cholesterol), whereas inverse associations were found with %ucOC. Men in the lowest quintile of ucOC had higher risk of MetS compared to men in the highest quintile (Q1 ≤ 7.7 vs Q5 > 13.8 ng/mL; OR = 2.4; 95% CI, 1.8-3.2). Men in the lowest quintile of cOC had higher risk of MetS compared to those in the highest quintile (≤ 5.8 vs > 13.0 ng/mL; OR = 2.4; 95% CI, 1.8-3.2).

CONCLUSION

Lower concentrations of serum ucOC or cOC were associated with less favorable metabolic parameters and a higher risk of MetS. In contrast, a lower proportion of ucOC was associated with better metabolic parameters and lower MetS risk. Further research is warranted to determine whether ucOC and cOC are suitable biomarkers for cardiometabolic risk in men.

Change in Circulating Undercarboxylated Osteocalcin (ucOCN) Is Associated With Fat Accumulation in HIV-Seropositive Women

BACKGROUND

Bone mineral density loss and fat accumulation are common in people living with HIV. The bone-derived hormone, undercarboxylated osteocalcin (ucOCN) regulates fat metabolism. We investigated the relationship between ucOCN change and body fat change among perimenopausal/postmenopausal HIV-seronegative and HIV-seropositive women on long-term antiretrovirals.

METHODS

Perimenopausal and postmenopausal women enrolled in the Women's Interagency HIV Study MSK substudy underwent trunk and total fat assessment by dual energy x-ray absorptiometry (DXA) at study enrollment (index visit) and again 2 years later. Circulating ucOCN and cOCN were also measured at the index and 2-year visits. The correlation between the 2-year change in ucOCN and cOCN and change in trunk and total fat was assessed as a function of HIV serostatus using linear regression modeling. Multivariate linear regression assessed the association between ucOCN and cOCN change and total and trunk fat change after adjusting for sociodemographic variables. Linear regression models restricted to HIV-seropositive women were performed to examine the contributions of HIV-specific factors (index CD4 count, viral load, and combined antiretroviral therapy use) on the associations.

RESULTS

Increased ucOCN over the 2-year follow-up was associated with less trunk and total fat accumulation in models adjusting for HIV serostatus and participants sociodemographics, whereas there was no association with cOCN and the fat parameters. None of the HIV-specific factors evaluated influenced the association between ucOCN and fat parameters.

CONCLUSION

The current study suggests that increases in ucOCN are associated with decreased fat accumulation in HIV-seronegative and HIV-seropositive postmenopausal women on long-term antiretroviral therapy.

Osteocalcin, Osteopontin and RUNX2 Expression in Patients' Leucocytes with Arteriosclerosis

Introduction: Calcification is a highly relevant process in terms of development of cardiovascular diseases, and its prevention may be the key to prevent disease progression in patients. In this study we investigated the expression of osteocalcin (OC), osteopontin (OPN) and RUNX2 in patients’ leukocytes and their possible role as diagnostic markers for cardiovascular diseases. Materials and Methods: Leucocytes from 38 patients were collected in the Department of Surgery of Martin-Luther-University Halle, including 8 patients without arteriosclerotic disease (PAD−) and 30 patients with symptomatic arteriosclerotic disease (PAD+). Patients’ leucocytes, in vitro calcified human umbilical vein endothelial cells (HUVEC) and vascular smooth muscle cells (VSMC) were subjected to qPCR analyses with TaqMan probes, which are specific for OC, OPN and RUNX2. Additionally, the interaction between monocytes and calcified HUVEC and VSMC was investigated in adhesion assays. Results: The leucocytes obtained from patients with symptomatic arteriosclerotic disease (PAD+) demonstrated decreased mRNA level expression of Osteocalcin, while OPN and RUNX2 were significantly upregulated in comparison to asymptomatic patients. The induction of calcification in HUVEC and VSMC cells led to an increased expression of OC, OPN and RUNX2. Immunocytochemistry of calcified HUVEC and VSMC revealed stronger expression of OC, OPN and RUNX2 in calcified cells. Conclusion: To conclude, these data demonstrate that symptomatic arteriosclerotic disease has a correlation with OC, OPN and RUNX2. The biological rationale of OC, OPN and RUNX-2 remains not yet entirely understood for atherosclerotic disease, which means it needs further investigation.

Osteocalcin and measures of adiposity: a systematic review and meta-analysis of observational studies

Osteocalcin, the osteoblast-derived protein, has been shown to be modulated in patients with problematic glucose metabolism. Our systematic review and meta-analysis found that in humans, higher blood osteocalcin level is associated with lower body indices of fat.

PURPOSE/INTRODUCTION

Osteocalcin (OC) was found to be inversely correlated with measures of glucose and energy metabolism, with some groups suggesting the undercarboxylated form (ucOC) to be metabolically active, although the link is not clear, especially in humans. Given obesity is a major risk factor for metabolic disorders, we aimed to assess the correlation between OC and two measures of body weight: body mass index (BMI) and percentage body fat (%BF).

METHODS

MEDLINE and EMBASE were searched to identify observational studies in adult populations that reported the crude correlation coefficients (r) between OC and BMI and %BF. Pool r were obtained using random-effects models.

RESULTS

Fifty-one publications were included in this analysis. Both total OC (TOC) (pooled r = - 0.151, 95% CI - 0.17, - 0.130; I² = 52%) and ucOC (pooled r = - 0.060, 95% CI - 0.103, - 0.016; I² = 54%) were inversely correlated with BMI. The pooled r between TOC and BMI in Caucasian-and-other-regions (r = - 0.187) were stronger than those in Asian populations (r = - 0.126; intra-group p = 0.002; R² = 0.21). The mean/median BMI of the reported cohort was the major contributor to between-study heterogeneity in correlation between TOC/ucOC and BMI (R² = 0.28 and 0.77, respectively). Both TOC and ucOC were also inversely correlated with %BF (TOC: pooled r = - 0.185, 95% CI - 0.257 to - 0.112; ucOC: pooled r = - 0.181, 95% CI - 0.258 to - 0.101).

CONCLUSION

Higher OC and ucOC were correlated with lower BMI and %BF. The inverse correlations between TOC/ucOC and BMI appear to be affected by ethnicity and obesity status.

The Role of Exercise in the Interplay between Myokines, Hepatokines, Osteokines, Adipokines, and Modulation of Inflammation for Energy Substrate Redistribution and Fat Mass Loss: A Review

Exercise is an effective strategy for preventing and treating obesity and its related cardiometabolic disorders, resulting in significant loss of body fat mass, white adipose tissue browning, redistribution of energy substrates, optimization of global energy expenditure, enhancement of hypothalamic circuits that control appetite-satiety and energy expenditure, and decreased systemic inflammation and insulin resistance. Novel exercise-inducible soluble factors, including myokines, hepatokines, and osteokines, and immune cytokines and adipokines are hypothesized to play an important role in the body's response to exercise. To our knowledge, no review has provided a comprehensive integrative overview of these novel molecular players and the mechanisms involved in the redistribution of metabolic fuel during and after exercise, the loss of weight and fat mass, and reduced inflammation. In this review, we explain the potential role of these exercise-inducible factors, namely myokines, such as irisin, IL-6, IL-15, METRNL, BAIBA, and myostatin, and hepatokines, in particular selenoprotein P, fetuin A, FGF21, ANGPTL4, and follistatin. We also describe the function of osteokines, specifically osteocalcin, and of adipokines such as leptin, adiponectin, and resistin. We also emphasize an integrative overview of the pleiotropic mechanisms, the metabolic pathways, and the inter-organ crosstalk involved in energy expenditure, fat mass loss, reduced inflammation, and healthy weight induced by exercise.

Negative impact of polycystic ovary syndrome on bone health: a systematic review and meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) has reproductive and metabolic aspects that may affect bone health. Controversial results from different studies regarding the risk of fractures, bone mineral density (BMD) or bone markers led to uncertainty whether PCOS might improve or deteriorate bone health.

OBJECTIVE AND RATIONALE

This study aimed to investigate the impact of PCOS on bone markers, BMD and fracture risk.

SEARCH METHODS

A systematic review and a meta-analysis were carried out. PubMed, EMBASE and Cochrane databases were searched for eligible studies from 1st of January of 1990 to 9th of October of 2018. Eligible studies enrolled women older than 18 years with PCOS, which should be diagnosed according to the Rotterdam Consensus, the Androgen Excess Society, the National Institutes of Health Consensus or the International Classification of Diseases. The studies were grouped according to patient mean BMI: <27 kg/m2 or ≥27 kg/m2. The results were polled as mean difference (MD), standardized MD (SMD) and hazard ratio (HR).

OUTCOMES

Overall, 921 studies were retrieved, and 31 duplicated studies were removed. After screening the titles and abstracts, 80 studies were eligible for full text reading. Of those, 23 studies remained for qualitative synthesis. With the exception of one study, all studies were considered high quality based on the Newcastle-Ottawa scale (NOS; score ≥6). Meta-analysis was performed in 21 studies, with a total of 31 383 women with PCOS and 102 797 controls. Women with PCOS with BMI <27 kg/m2 had lower BMD of the total femur (MD, -0.04; 95% CI, -0.07 to 0.00; I2 = 31%; P = 0.22) and spine (MD, -0.07; 95% CI, -0.13 to -0.01; I2 = 70%; P < 0.01) when compared with the control group, whereas for women with BMI ≥27 kg/m2 no difference was observed (femur: MD, 0.02; 95% CI, -0.02 to 0.05; I2 = 20%, P = 0.29; spine: MD, 0.02; 95% CI, -0.06 to 0.05; I2 = 0%; P = 0.84). Osteocalcin was remarkably reduced in women with PCOS with BMI <27 kg/m2 (SMD, -2.68; 95% CI, -4.70 to -0.67; I2 = 98%; P < 0.01), but in women with BMI ≥27 kg/m2, there were no differences between PCOS and controls. Few studies (n = 3) addressed the incidence of bone fractures in women with PCOS. The HR for total bone fractures did not identify differences between women with PCOS and controls.

WIDER IMPLICATIONS

On the basis of the available evidence, it is possible to assume that PCOS in women with BMI <27 kg/m2 is associated with reduced BMD in the spine and femur, and decreased bone formation, as manifested by lower levels of circulating osteocalcin. These findings suggest that bone parameters in PCOS may be linked, to some extent, to adiposity. These studies included premenopausal women, who have already achieved peak bone mass. Hence, further prospective studies are necessary to clarify the existence of increased risk of fractures in women with PCOS.

Lower serum osteocalcin concentrations in patients with type 2 diabetes and relationships with vascular risk factors among patients with coronary artery disease

BACKGROUND

Lower serum concentrations of the osteoblast-derived protein, osteocalcin, have been associated with poorer glycemic control, insulin resistance and atherosclerosis, and with the development of type 2 diabetes (T2DM).

METHODS

This study compares concentrations of two physiological forms of osteocalcin, carboxylated (cOCN) and uncarboxylated (unOCN), between participants with T2DM (n = 20) and age-, gender- and body mass index (BMI)-matched participants without T2DM (n = 40) among patients with coronary artery disease (CAD), and it explores relationships between osteocalcin concentrations and cardiovascular risk factors.

RESULTS

Concentrations of unOCN (2.71 ± 1.86 vs. 4.70 ± 2.03 ng/mL; t = -3.635, p = 0.001) and cOCN (8.70 ± 2.27 vs. 10.77 ± 3.69 ng/mL; t = -2.30, p = 0.025) were lower in participants with T2DM. In participants without T2DM, concentrations of cOCN were associated with fitness (VO_2Peak rho = 0.317, p = 0.047) and lower body fat (rho = -0.324, p = 0.041). In participants with T2DM, lower unOCN was associated with HbA1c (rho = -0.516, p = 0.020). Higher body mass was associated with higher unOCN (rho = 0.423, p = 0.009) in participants without T2DM, but with lower concentrations of both unOCN (rho = -0.590, p = 0.006) and cOCN (rho = -0.632, p = 0.003) in participants with T2DM.

CONCLUSION

In patients with CAD, lower osteocalcin concentrations were related to type 2 diabetes, and to adverse fitness, metabolic and obesity profiles.

Association of body mass index and waist circumference with osteocalcin and C-terminal telopeptide in Iranian elderly: results from a cross-sectional study

There is no agreement on the role of obesity as a protection or unfavorable factor on bone. In the present study, the association of body mass index (BMI) and waist circumference (WC) with osteocalcin, C-terminal telopeptide of type 1 collagen (CTX-I), highly sensitive C-reactive protein (hs-CRP), parathormon (PTH) and 25-hydroxyvitamin D (25(OH)D) in elderly people was investigated. This cross-sectional study was conducted on 178 elderly residents in Tehran, with a mean age of 67.04 (60-83). Serum osteocalcin, hs-CRP, 25(OH) D, PTH and urine CTX-I were measured for all participants. Waist circumference, weight and height were measured and BMI was calculated. Linear regression and Pearson correlation were performed to evaluate the relation of BMI and waist circumference with other variables. A significant inverse association was found between BMI with osteocalcin (β = - 0.171, p = 0.027) after control for covariates. In addition, there were a significant relation of BMI and WC with hs-CRP (β = 0.246, p = 0.002 and β = 0.219, p = 0.006, respectively) and PTH (β = 0.1169, p = 0.040 and β = 0.200, p = 0.018), respectively. The present study did not show a significant relation of BMI and WC with urine CTX-I even after adjustment for potential confounders (β = - 0.143, p = 0.065 and β = - 0.104, p = 0.183, respectively). The present study has concluded that obesity is an undesirable factor for bone metabolism by reducing serum osteocalcin and by increasing hs-CRP and PTH which contribute to bone resorption.