Relationship between leptin, adiponectin, bone mineral density, and measures of adiposity among pre-menopausal Hispanic and Caucasian women

Differences in metabolic biomarkers in people with schizophrenia who are of Mexican descent compared to non-Hispanic whites

Metabolic dysfunction is highly prevalent and contributes to premature mortality among people with schizophrenia (PwS), especially in Hispanic/Latino/a/x/e PwS, compared to non-Hispanic White (NHW) PwS. This study evaluated the relative contributions of Mexican descent and schizophrenia diagnosis to metabolic biomarker levels. This cross-sectional study included 115 PwS and 102 non-psychiatric comparison (NC) participants - English-speakers aged 26-66 years, 27% Mexican descent, and 52% women across both groups. Assessments included evaluations of BMI, psychopathology, and fasting metabolic biomarkers. We used ANOVA analyses to compare metabolic outcomes between diagnostic and ethnic subgroups, linear regression models to examine associations between Mexican descent and metabolic outcomes, and Spearman's correlations to examine relationships between metabolic outcomes and illness-related variables in PwS. Mexican PwS had higher hemoglobin A1c levels, insulin resistance, and body mass index than NHW PwS. Mexican descent was associated with higher hemoglobin A1c levels, insulin resistance, body mass index, and leptin levels, controlling for age, sex, depression, education, and smoking. Among Mexican PwS, worse negative symptoms were associated with greater insulin resistance. These findings support the possibility of ethnicity-based differences in metabolic dysregulation, though further investigation is warranted to create targeted health interventions for Hispanic PwS.

Effect of adipokine and ghrelin levels on BMD and fracture risk: an updated systematic review and meta-analysis

Context

Circulating adipokines and ghrelin affect bone remodeling by regulating the activation and differentiation of osteoblasts and osteoclasts. Although the correlation between adipokines, ghrelin, and bone mineral density (BMD) has been studied over the decades, its correlations are still controversial. Accordingly, an updated meta-analysis with new findings is needed.

Objective

This study aimed to explore the impact of serum adipokine and ghrelin levels on BMD and osteoporotic fractures through a meta-analysis.

Data sources

Studies published till October 2020 in Medline, Embase, and the Cochrane Library were reviewed.

Study selection

We included studies that measured at least one serum adipokine level and BMD or fracture risk in healthy individuals. We excluded studies with one or more of the following: patients less than 18 years old, patients with comorbidities, who had undergone metabolic treatment, obese patients, patients with high physical activities, and a study that did not distinguish sex or menopausal status.

Data extraction

We extracted the data that include the correlation coefficient between adipokines (leptin, adiponectin, and resistin) and ghrelin and BMD, fracture risk by osteoporotic status from eligible studies.

Data synthesis

A meta-analysis of the pooled correlations between adipokines and BMD was performed, demonstrating that the correlation between leptin and BMD was prominent in postmenopausal women. In most cases, adiponectin levels were inversely correlated with BMD. A meta-analysis was conducted by pooling the mean differences in adipokine levels according to the osteoporotic status. In postmenopausal women, significantly lower leptin (SMD = -0.88) and higher adiponectin (SMD = 0.94) levels were seen in the osteoporosis group than in the control group. By predicting fracture risk, higher leptin levels were associated with lower fracture risk (HR = 0.68), whereas higher adiponectin levels were associated with an increased fracture risk in men (HR = 1.94) and incident vertebral fracture in postmenopausal women (HR = 1.18).

Conclusions

Serum adipokines levels can utilize to predict osteoporotic status and fracture risk of patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021224855, identifier CRD42021224855.

Osteosarcopenic obesity, the coexistence of osteoporosis, sarcopenia and obesity and consequences in the quality of life in older adults ≥65 years-old in Greece

OBJECTIVE

We investigated the coexistence of sarcopenia and obesity in older adults≥65 years diagnosed with osteoporosis and the association with Quality of Life (QoL).

METHODS

A Cross-sectional survey has been performed on a randomized sample of 50 diagnosed osteoporotic elderly people from both sexes (Men=16; Women=34).

MEASUREMENTS

Quantitative ultrasound was conducted to identify osteoporosis and defined with a T score ≤2.5. Validated anthropometric equations were used in order to estimate body fat percentage and skeletal muscle mass so as to detect the reallocation of body fat and lean muscle. 10m gait speed and hand grip strength was measured in order to diagnose sarcopenia according to European Society for Clinical Nutrition and Metabolism (ESPEN) algorithm. The evaluation of QoL was conducted using a QoL questionnaire specific to osteoporosis. The data were analyzed with descriptive statistics and a chi-square test was performed to examine if Osteosarcopenic Obesity (OSO) is sex related and the correlation between OSO and QoL.

RESULTS

From the 50 participants, 40%(n=19) were classified as people with OSO and 60%(n=31) without OSO. From n=19 people that experienced OSO women represent 20% (n=9) and men 18% (n=9); with the latter had a greater decline in muscle mass than women, while women had lower BMD than men according to the z score. OSO is not related with sex (p>.05) and there is no significant association between OSO and QoL (p> .05 for all the domains of QoL questionnaire).

CONCLUSION

Osteoporosis in the elderly often coexists with reduced muscle mass and muscle strength as well as an increase in adiposity and was independently associated with QoL. People that experience OSO presenting lower functionality that increases the risk for falls and bone fractures originated from the decline in bone and muscle mass, and increased adiposity. Increased awareness of OSO may help develop efficient interventions and public health policies for healthier and more active elderly people.

Adiponectin signaling and its role in bone metabolism

Adiponectin, the most prevalent adipo-cytokine in plasma plays critical metabolic and anti-inflammatory roles is fast emerging as an important molecular target for the treatment of metabolic disorders. Adiponectin action is critical in multiple organs including cardio-vascular system, muscle, liver, adipose tissue, brain and bone. Adiponectin signaling in bone has been a topic of active investigation lately. Human association studies and multiple mice models of gene deletion/modification failed to define a clear cause and effect of adiponectin signaling in bone. The most plausible reason could be the multimeric forms of adiponectin that display differential binding to receptors (adipoR1 and adipoR2) with cell-specific receptor variants in bone. Discovery of small molecule agonist of adipoR1 suggested a salutary role of this receptor in bone metabolism. The downstream signaling of adipoR1 in osteoblasts involves stimulation of oxidative phosphorylation leading to increased differentiation via the likely suppression of wnt inhibitor, sclerostin. On the other hand, the inflammation modulatory effect of adiponectin signaling suppresses the RANKL (receptor activator of nuclear factor κ-B ligand) - to - OPG (osteprotegerin) ratio in osteoblasts leading to the suppression of osteoclastogenic response. This review will discuss the adiponectin signaling and its role in skeletal homeostasis and critically assess whether adipoR1 could be a therapeutic target for the treatment of metabolic bone diseases.

Ethnic and Sex Differences in Adiponectin: From Childhood to Adulthood

CONTEXT

Insulin resistance (IR) and type 2 diabetes are increasing, particularly in Hispanic (H) vs non-Hispanic White (NHW) populations. Adiponectin has a known role in IR, and therefore, understanding ethnic and sex-specific behavior of adiponectin across the lifespan is of clinical significance.

OBJECTIVE

To compare ethnic and sex differences in adiponectin, independent of body mass index, across the lifespan and relationship to IR.

DESIGN

Cross-sectional.

SETTING

Primary care, referral center.

PATIENTS

A total of 187 NHW and 117 H participants (8-57 y) without diabetes. Life stage: pre-/early puberty (Tanner 1/2), midpubertal (Tanner 3/4), late pubertal (Tanner 5, <21 years), and adult (Tanner 5, ≥21).

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

Fasting adiponectin, insulin, glucose, and revised homeostatic model assessment of insulin resistance.

RESULTS

Adiponectin was significantly inversely correlated with revised homeostatic model assessment of insulin resistance. Regarding puberty, adiponectin trended downward in late puberty, but only males were significantly lower in adulthood. By sex, adiponectin was lower in adult males vs females of both ethnicities. Regarding ethnicity, H adults of both sexes had lower adiponectin than NHW adults. Of note, in NHW females, adiponectin trended highest in adulthood, whereas in H females, adiponectin fell in late puberty and remained lower in adulthood.

CONCLUSIONS

Adiponectin inversely correlated with IR, trended down in late puberty, and was lowest in adult males. H adults of both sexes had lower adiponectin than NHW adults, and H females followed a more "male pattern," lacking the rebound in adiponectin seen in NHW females after puberty. These data suggest that adiponectin, independent of body mass index, may relate to the greater cardiometabolic risk seen in H populations and in particular H females.

Correlation between serum leptin and bone mineral density in hemodialysis patients

Introduction: For diagnosing of specific types of bone lesions in hemodialysis (HD) patients, it is necessary to conduct a bone biopsy as the gold standard method. However, it is an invasive procedure. While different markers have been suggested as alternative methods, none of them has been selected. The frequency of hip fractures is 80 fold in HD patients who have two-fold mortality as compared with general population.

Objectives: Recently, serum leptin has been suggested as a bone density marker. This study tries to confirm this proposal.

Patients and Methods: In this study about 104 HD patients (53.8% male and 46.2% female) were enrolled. The average age was 38.28±7.89 years. Serum leptin, bone alkaline phosphatase, intact parathyroid hormone (iPTH), 25(OH)D, calcium, phosphorus and bone mineral density (BMD) (at the femoral neck and lumbar spine, as measured by dual-energy x-ray absorptiometry [DXA]) were assessed.

Results: Analysis by polynomial regression revealed no correlation between BMD Z-score at two points and serum leptin level. According to the thresholds of 25 ng/mL and 18-24 ng/mL in some studies, we detected 25 ng/mL as the threshold in our patients. Under this threshold, the leptin effect on bone mass was negative, and above the threshold of 25 ng/mL, we found leptin had positive effect on bone mass.

Conclusion: In this investigation, we found, leptin has a bimodal effect on bone mass. Cortical bones assessment may be a better option for assessment.

Expressions and clinical significance of serum bone Gla-protein, bone alkaline phosphatase and C-terminal telopeptide of type I collagen in bone metabolism of patients with osteoporosis

OBJECTIVE

This study aimed to evaluate the expressions and clinical significance of bone Gla-protein (BGP), bone alkaline phosphatase (B-ALP) and C-terminal telopeptide of type I collagen (CTX) in patients with osteoporosis (OP), and to provide evidence for developing individualized treatment plans.

METHODS

Seventy-two OP patients in our hospital were selected as an OP group, and another 72 healthy subjects were used as a control group. Their BGP, B-ALP and CTX levels as well as bone mineral density (BMD) values were measured. The correlations between BGP, B-ALP and CTX levels and BMD values were determined.

RESULTS

The BGP level of the OP group [(5.61±5.52) ng/ml] was significantly higher than that of the control group (P<0.05), but the levels of B-ALP and CTX did not differ significantly (P>0.05). The BMD values of femoral neck and Ward's triangle in the OP group were negatively correlated with the B-ALP levels (P<0.05). For women OP patients, the BMD values of femoral neck and Ward's triangle were also negatively correlated with the B-ALP levels (P<0.05). The BMD of femoral neck in the control group was negatively correlated with the CTX level (P<0.05).

CONCLUSION

Determining BGP, B-ALP and CTX levels can evaluate the bone metabolism degree, which provides evidence for clinical typing of OP and developing treatment strategies.

Relationship between serum leptin levels and bone mineral density: a systematic review and meta-analysis

BACKGROUND

The association between leptin and bone mineral density (BMD) is controversial because of conflicting findings from previous studies.

METHODS

This meta-analysis aimed to provide an overview of the serum leptin levels and BMD in a healthy population. We reviewed the PubMed, Embase, and Cochrane Library databases until July 2014 for research on the association between leptin levels and BMD in healthy people.

RESULTS

We included and analyzed 45 studies in this systematic review and meta-analysis. The pooled correlations between leptin and BMD were analyzed by using the method of the inverse of the variance. Leptin was positively associated with BMD and the bone mineral content (BMC), especially in postmenopausal women (pooled r: 0.13-0.49). Overall, high serum leptin levels were associated with higher BMD levels.

CONCLUSIONS

This meta-analysis suggests that serum leptin levels are positively associated with BMD and BMC, especially in postmenopausal women.

Bone metabolism and adipokines: are there perspectives for bone diseases drug discovery?

INTRODUCTION

Over the past 20 years, the idea that white adipose tissue (WAT) is simply an energy depot organ has been radically changed. Indeed, present understanding suggests WAT to be an endocrine organ capable of producing and secreting a wide variety of proteins termed adipokines. These adipokines appear to be relevant factors involved in a number of different functions, including metabolism, immune response, inflammation and bone metabolism.

AREAS COVERED

In this review, the authors focus on the effects of several adipose tissue-derived factors in bone pathophysiology. They also consider how the modification of the adipokine network could potentially lead to promising treatment options for bone diseases.

EXPERT OPINION

There are currently substantial developments being made in the understanding of the interplay between bone metabolism and the metabolic system. These insights could potentially lead to the development of new treatment strategies and interventions with the aim of successful outcomes in many people affected by bone disorders. Specifically, future research should look into the intimate mechanisms regulating peripheral and central activity of adipokines as it has potential for novel drug discovery.

Links between obesity, diabetes and ethnic disparities in breast cancer among Hispanic populations

Breast cancer is the most prevalent malignancy in women worldwide and is a growing concern due to rising incidence and ongoing ethnic disparities in both incidence and mortality. A number of factors likely contribute to these trends including rising rates of obesity and diabetes across the globe and differences in genetic predisposition. Here, we emphasize Hispanic populations and summarize what is currently known about obesity, diabetes and individual genetic predisposition as they relate to ethnic disparities in breast cancer incidence and mortality. In addition, we discuss potential contributions to breast cancer aetiology from molecular mechanisms associated with obesity and diabetes including dyslipidemia, hyperglycaemia, hyperinsulinaemia, endocrine dysfunction and inflammation. We propose that unique differences in diet and lifestyle coupled with individual genetic predisposition and endocrine/immune dysfunction explain most of the ethnic disparities seen in breast cancer incidence and mortality.

Novel adipokines and bone metabolism

Osteoporosis is a serious social issue nowadays. Both the high morbidity and its common complication osteoporotic fracture load a heavy burden on the whole society. The adipose tissue is the biggest endocrinology organ that has a different function on the bone. The adipocytes are differentiated from the same cell lineage with osteoblast, and they can secrete multiple adipokines with various functions on bone remolding. Recently, several novel adipokines have been identified and investigated thoroughly. In this paper, we would like to highlight the complicated relation between the bone metabolism and the novel adipokines, and it may provide us with a new target for prediction and treatment of osteoporosis.

Serum adiponectin in relation to race-ethnicity and vascular risk factors in the Northern Manhattan Study

BACKGROUND

Population-based data on serum adiponectin levels, an adipocytokine secreted from adipose tissue, are lacking, particularly across race-ethnic groups. Studies have suggested an inverse association between adiponectin and vascular risk factors, but data are limited and inconsistent. We examined the cross-sectional association between adiponectin, vascular risk factors and race-ethnicity in the population-based Northern Manhattan Study (NOMAS).

METHODS

Blood samples, anthropomorphics, and vascular risk factors were collected at baseline. Multivariable linear regression analysis was conducted with log-transformed adiponectin as the dependent variable.

RESULTS

Adiponectin was measured among 2900 participants (age 69±10 years, body mass index (BMI) 28.0±5.6, 37% male, 21% white, 53% Hispanic, 24% black). The mean adiponectin was 11.4±6.2 μg/mL (median=9.8, range=2.1-53.3). After multivariable adjustment, adiponectin levels were greatest among whites, followed by Hispanics, and lowest among blacks. Lower adiponectin levels were observed in participants with the following characteristics: Male, former smoking, hypertension, diabetes, homeostasis model assessment of insulin resistance (HOMA-IR), metabolic syndrome, moderate alcohol use, elevated waist circumference, BMI, estimated glomerular filtration rate (eGFR), triglycerides, low-density lipoprotein cholesterol (LDL-C), lower high-density lipoprotein cholesterol (HDL-C), and younger age. Obesity was a stronger risk factor for decreased adiponectin among blacks than among whites or Hispanics. The associations for several vascular risk factors, including hypertension, triglycerides, and low HDL-C, with low adiponectin were stronger among individuals who were not obese than among those who were obese.

CONCLUSIONS

Adiponectin levels were lower among blacks and Hispanics and among those with various vascular risk factors, and greater with older age. The association between BMI and adiponectin varied across race-ethnic groups. Investigation of whether differences in body fat distribution may explain race-ethnic differences in adiponectin is needed.

High serum adiponectin predicts incident fractures in elderly men: Osteoporotic fractures in men (MrOS) Sweden

Adipocytes and osteoblasts share a common progenitor, and there is, therefore, potential for both autocrine and endocrine effects of adiponectin on skeletal metabolism. The aim of the present study was to determine whether high serum adiponectin was associated with an increased risk of fracture in elderly men. We studied the relationship between serum adiponectin and the risk of fracture in 999 elderly men drawn from the general population and recruited to the Osteoporotic Fractures in Men (MrOS) study in Gothenburg, Sweden. Baseline data included general health questionnaires, lifestyle questionnaires, body mass index (BMI), bone mineral density (BMD), serum adiponectin, osteocalcin, and leptin. Men were followed for up to 7.4 years (average, 5.2 years). Poisson regression was used to investigate the relationship between serum adiponectin, other risk variables and the time-to-event hazard function of fracture. Median levels of serum adiponectin at baseline were 10.4 µg/mL (interquartile range, 7.7-14.3). During follow-up, 150 men sustained one or more fractures. The risk of fracture increased in parallel with increasing serum adiponectin (hazard ratio [HR]/SD, 1.46; 95% confidence interval [CI], 1.23-1.72) and persisted after multivariate-adjusted analysis (HR/SD, 1.30; 95% CI, 1.09-1.55). Serum adiponectin shows graded stepwise association with a significant excess risk of fracture in elderly men that was independent of several other risk factors for fracture. Its measurement holds promise as a risk factor for fracture in men.

Adiponectin interactions in bone and cartilage biology and disease

The adipokine adiponectin promotes insulin sensitivity and fat β-oxidation. In addition to its metabolic effects, adiponectin is an important local and systemic modulator of bone remodeling and cartilage biology, involving direct and indirect mechanisms and a large set of downstream molecular signals. Moreover, data suggest that changes in adiponectin signaling may be associated with bone and cartilage diseases. Adiponectin seems to exert a negative net effect on bone mass and to be an independent predictor of lower bone mass, whereas available data about actions on cartilage are more controversial, showing both pro- and anti-inflammatory actions. Adiponectin-bone cross talk seems to be reciprocal, as osteocalcin, produced by osteoblasts, has been shown to stimulate adiponectin expression and to improve glucose tolerance. Adiponectin-related signaling in bone and cartilage should be considered within the network of hormonal and nutritional signals that may influence skeleton biology, together with body homeostasis and adipose mass changes.

Type 2-diabetes is associated with elevated levels of TNF-alpha, IL-6 and adiponectin and low levels of leptin in a population of Mexican Americans: a cross-sectional study

The goal of the study was to determine the association between diabetes and inflammation in clinically diagnosed diabetes patients. We hypothesized that low-grade inflammation in diabetes is associated with the level of glucose control. Using a cross-sectional design we compared pro- and anti-inflammatory cytokines in a community-recruited cohort of 367 Mexican Americans with type 2-diabetes having a wide range of blood glucose levels. Cytokines (IL-6, TNF-α, IL-1β, IL-8) and adipokines (adiponectin, resistin and leptin) were measured using multiplex ELISA. Our data indicated that diabetes as whole was strongly associated with elevated levels of IL-6, leptin, CRP and TNF-α, whereas worsening of glucose control was positively and linearly associated with high levels of IL-6, and leptin. The associations remained statistically significant even after controlling for BMI and age (p=0.01). The association between TNF-α, however, was attenuated when comparisons were performed based on glucose control. Strong interaction effects between age and diabetes and BMI and diabetes were observed for IL-8, resistin and CRP. The cytokine/adipokine profiles of Mexican Americans with diabetes suggest an association between low-grade inflammation and quality of glucose control. Unique to in our population is that the chronic inflammation is accompanied by lower levels of leptin.