scholarly journals The in vitro secretion of human leptin is gender-dependent but independent of the body mass index of the donors

2000 ◽  
pp. 711-714 ◽  
Author(s):  
C Menendez ◽  
R Baldelli ◽  
M Lage ◽  
X Casabiell ◽  
V Pinero ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Tissue Sample ◽  
Secretory Activity ◽  
The Body ◽  
Secretory Rate ◽  
Omental Adipose Tissue

OBJECTIVE: Leptin is an adipocyte-secreted hormone acting as a signal to the central nervous system, where it regulates energy homeostasis and neuroendocrine processes. Leptin plasma levels are mainly regulated by the percentage of body fat, but are also controlled by several metabolic and nutritional variables. Data regarding leptin secretion suggest that it is gender regulated, and higher levels are present in women than men; however, the biological basis for this sex-related difference is unknown. To clarify those points, a systematic study with tissue cultures from human omental adipose tissue was performed. DESIGN AND METHODS: Surgically obtained samples from 137 patients (68 women, 69 men) were evaluated. The assay was standardized in periods of 24 h ending at 96 h. Each adipose tissue sample from a single donor was incubated in triplicate and leptin results expressed as the mean of the integrated secretion into the medium (nanograms of leptin/g tissue per time). RESULTS: Tissue adipose cultures showed a steady leptin secretion throughout the 96 h studied, with the peak of secretory activity reached at 48 h; afterwards, the in vitro secretion reached a plateau state. Spontaneous leptin secretion in the 24 h and 48 h period, as well as the area under the curve analyzed in the 0-48 h period, showed a gender-based difference that was significantly (P<0. 05) higher in women than in men. When data of spontaneous leptin secretion were correlated with the body mass index (BMI) of the donors, no correlation was found. This suggests that in vivo leptin levels are dependent on the total amount of fat of the individual, but independent of the leptin secretory rate by the adipose tissue of the donor. CONCLUSIONS: Leptin secretion from omental adipose tissue in vitro is: (i) significantly higher in samples from women than in samples from men; and (ii) not correlated with the BMI, showing that in vitro leptin secretion is not related to the adiposity of the donor.

scholarly journals Gender Differences in Both Spontaneous and Stimulated Leptin Secretion by Human Omental Adipose Tissue in Vitro: Dexamethasone and Estradiol Stimulate Leptin Release in Women, But Not in Men1

1998 ◽  
Vol 83 (6) ◽  
pp. 2149-2155 ◽  
Author(s):  
Xesús Casabiell ◽  
Verónica Piñeiro ◽  
Roberto Peino ◽  
Mary Lage ◽  
Jesús Camiña ◽  
...  
Keyword(s):  
Gender Differences ◽  
Adipose Tissue ◽  
Energy Homeostasis ◽  
Tissue Sample ◽  
Intrinsic Property ◽  
Secretory Activity ◽  
Omental Adipose Tissue ◽  
Adipose Tissue In Vitro ◽  
Human Omental Adipose Tissue

Leptin is a hormone secreted by the adipocytes to serve as a signal to the central nervous system to regulate energy homeostasis. Circulating leptin mainly reflects both total fat mass and the size of constituent adipocytes, although other ancillary hormonal factors may contribute to its blood concentration. Relevant gender differences in leptin concentrations have been reported, but it is not clear whether the elevated leptin levels in women are an intrinsic property of their adipocytes or merely reflect a greater amount of fat reserves. To clarify these points, a systematic study with organ culture from human omental adipose tissue either stimulated or not with steroid hormones was undertaken in samples obtained at surgery from 67 nonobese donors (33 women and 34 men). The assay was standardized in periods of 24 h ending at 96 h, with no apparent tissue damage. Each adipose tissue sample from a single donor was incubated in triplicate, and leptin results are expressed as the mean ± sem of the integrated secretion to the medium (area under the curve; nanograms of leptin per g tissue/48 h). Control nonstimulated samples showed a steady leptin secretion along the 96 h studied, with the peak of secretory activity reached at 48 h; afterward, the in vitro secretion reached a plateau state. Spontaneous leptin secretion in samples from 33 women (3904 ± 347) was significantly higher (P &lt; 0.05) than that in samples from 34 men (2940 ± 323). Coincubation of adipose tissue with 1 μmol/L dexamethasone induced a clear-cut leptin increase (P &lt; 0.05) in samples from women (5848 ± 624; n = 12), but did not change the spontaneous release of leptin in samples from men (3353 ± 741; n = 6). Similarly, coincubation of adipose tissue with 1 μmol/L estradiol induced a notable leptin increase (P &lt; 0.05) in samples from women (5698 ± 688; n = 9), whereas it did not alter the secretion in the male samples (3373 ± 444; n = 6). In samples from both sexes, coincubation with 1 μmol/L estrone or progesterone had no effect, whereas 1 μmol/L forskolin significantly (P &lt; 0.05) reduced leptin release. In conclusion, leptin secretion from omental adipose tissue in vitro 1) is significantly higher in samples from women than in samples from men, 2) is stimulated by dexamethasone and estradiol in women but not in men, 3) is not modified by progesterone or estrone in both sexes, and 4) is inhibited by forskolin in both genders. This different response to the stimulation of adipose tissue may be the biological basis for the gender differences observed in circulating levels of human leptin.

scholarly journals SAT-126 Breast Adipose Tissue Extracellular Vesicles from Obese Women Increase Breast Cancer Aggressiveness - a Novel Mechanism for the Obesity-Breast Cancer Link

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Alberto Benito-Martin ◽  
Paul Paik ◽  
Malik Mushannen ◽  
Priya Bhardwaj ◽  
Sonya Oshchepkova ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Extracellular Vesicles ◽  
Human Breast ◽  
Mouse Xenograft Model ◽  
Breast Adipose Tissue ◽  
Breast Adipose

Abstract Background and Objectives: Breast cancer is among the most common cancer in women with 2.1 million new cases detected each year. Numerous studies have demonstrated a connection between body mass index (BMI) and cancer incidence, with obesity (BMI ≥ 30) being responsible for the development of at least 13 types of cancer, and 15% to 20% of total cancer-related mortality. The effects of extracellular vesicles (EVs) derived from the obese adipose tissue microenvironment on breast cancer have not yet been clearly elucidated. Methods: EVs were obtained from media conditioned with human breast adipose tissue from reduction mammoplasty (n=31). Women were healthy at the time of surgery and had no history of breast cancer. Patient samples were stratified based on their body mass index (BMI), with a BMI &lt; 25 considered healthy and a BMI ≥ 25 considered overweight/obese. Breast adipose tissue-derived EVs (AT-EVs) were characterized (Quantitative Mass Spectrometry) and used to treat human breast cancer cell lines, including the ER+ MCF7 and triple negative breast cancer (TNBC) MDA-MB-231. Effects on cell proliferation and migration in vitro, and on tumor growth in a mouse xenograft model, were examined after long-term education with EVs. RNA sequencing was performed to investigate potential reprogramming induced by AT-EVs. Results: We found a positive correlation between protein amount per AT-EV and BMI. Quantitative proteomics of AT-EVs revealed 46 proteins that were significantly higher and 54 proteins that were significantly lower in specimens from women with a BMI ≥ 25 compared to women with a BMI &lt; 25. AT-EVs from patients with a BMI ≥ 25 induced proliferation of MCF7 cells compared to AT-EVs from patients with a BMI &lt; 25. Obese EVs induced a more aggressive phenotype in MDA-MB-231 cells, increasing their invasiveness in vitro. Obese EVs also increased the growth of MCF7 and MDA-MB-231 cells in vivo. Ingenuity pathway analysis of RNA-Seq data identified significant differences in mTOR signaling and canonical pathways associated with altered mitochondrial function. Conclusion: Our studies identify a novel mechanism to explain the obesity-breast cancer link in older women. Namely, that in obesity, the breast microenvironment produces EVs capable of reprogramming breast cancer cells to grow faster and be more aggressive. Identifying which cargo in breast AT-EV mediates these effects may provide new targets for intervention.

scholarly journals Interstitial Glucose and Lactate Levels Are Inversely Correlated With the Body Mass Index: Need for In Vivo Calibration of Glucose Sensor Results With Blood Values in Obese Patients

2017 ◽  
Vol 12 (2) ◽  
pp. 341-348 ◽  
Author(s):  
Barbara Enderle ◽  
Isabella Moser ◽  
Cecil Kannan ◽  
Karl Otfried Schwab ◽  
Gerald Urban
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Glucose Sensor ◽  
Reference Method ◽  
The Body ◽  
Blood Levels ◽  
Interstitial Glucose ◽  
Lactate Levels ◽  
In Vivo Calibration

Background: Continuously measured glucose and lactate levels in interstitial fluid (ISF) may markedly differ from their respective blood levels. Methods: Combining microdialysis with a bioanalytical microsystem, the interstitial glucose and lactate concentrations of eight male volunteers with different body mass index (BMI) were monitored during a 2-fold glucose tolerance test over the period of three hours. Results: Significant correlations were found between abdominally measured sensor results and reference measurements ( R2 = .967 for glucose and R2 = .936 for lactate, P < .05). The physiological delay of the abdominally observed glucose appearance in the ISF correlated positively with the BMI ( R2 = .787, P < .05). The relative in vivo recovery of glucose and lactate was inversely proportional to the BMI of the volunteers ( R2 = .540 for glucose, R2 = .609 for lactate, P < .05). One subject with a BMI of > 34 kg/m2 showed abdominally as well as the antebrachially significantly reduced tissue glucose values compared to blood glucose values ( P < .001). Conclusions: A very good correlation between abdominally measured sensor results and the results of the reference method verified the reliability of the BioMEMS. The abdominally measured glucose level in ISF decreased significantly with increasing BMI. Therefore, an in vivo calibration of glucose levels in ISF with blood levels seems to be necessary especially in markedly obese subjects.

scholarly journals The Relation of Body Mass Index to Muscular Viscoelastic Properties in Normal and Overweight Individuals

Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1022
Author(s):  
Serkan Usgu ◽  
Engin Ramazanoğlu ◽  
Yavuz Yakut
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Viscoelastic Properties ◽  
Biceps Brachii ◽  
Mechanical Load ◽  
Muscle Tone ◽  
Biceps Femoris ◽  
Normal Weight ◽  
The Body

Background: The body mass index (BMI) is closely related to fat tissue, which may have direct or indirect effects on muscle function. Previous studies have evaluated BMI and muscle viscoelastic properties in vivo in older people or individual sexes; however, the relationship between BMI and muscular viscoelastic properties is still unknown. Aims: The purpose of this study was to determine the correlation of BMI with muscular viscoelastic properties, and to compare these properties in a young sedentary population with normal and overweight individuals. Methods: A total of 172 healthy sedentary individuals (mean age, 26.00 ± 5.45 years) were categorized by sex (male and female) and BMI classification (normal (BMI, 18.50–24.99 kg/m2), overweight (BMI = 25.00–29.99 kg/m2)). Body weight was evaluated using an electronic scale, while height was measured using a standard stadiometer. BMI was calculated by dividing the weight in kilograms by the square of height in meters. The viscoelastic properties (tone, stiffness, and elasticity) of the biceps brachii (BB) and biceps femoris (BF) muscles were measured bilaterally using the MyotonPRO device at rest. Results: The bilateral BF tone and stiffness, right BB stiffness, and elasticity showed weak correlations with BMI in all participants. Furthermore, the bilateral BF tone and stiffness, right BB stiffness and elasticity, and left BB stiffness were weakly positively correlated with male sex. Only the right BB elasticity was weakly positively correlated with BMI in females (p < 0.05). No correlation with BMI was determined for other viscoelastic properties (p > 0.05). The overweight group showed increased bilateral BF stiffness and tone, right BB stiffness, and reduced bilateral BB elasticity compared to the normal-weight group (p < 0.05), while other viscoelastic properties were similar (p > 0.05). Greater bilateral BB tone, BF tone and stiffness, and lower BF elasticity were observed in males than in females (p < 0.05), but other viscoelastic properties were not significantly different (p < 0.05). No effect of BMI–sex interactions was found on viscoelastic properties (p > 0.05). Conclusions: The BB and BF viscoelastic properties were weakly correlated with BMI. Males showed greater muscle tone and stiffness, and lower elasticity. The overweight individuals showed increased stiffness and tone, particularly in lower extremities, and reduced elasticity in upper extremities. The effect of BMI–sex interactions on the viscoelastic properties was not clear. Higher BMI (increased mechanical load) might cause the human body to develop different muscular viscoelastic adaptations in the extremities.

scholarly journals Lower Zinc-α2-Glycoprotein Production by Adipose Tissue and Liver in Obese Patients Unrelated to Insulin Resistance

2009 ◽  
Vol 94 (11) ◽  
pp. 4499-4507 ◽  
Author(s):  
David M. Selva ◽  
Albert Lecube ◽  
Cristina Hernández ◽  
Juan A. Baena ◽  
José M. Fort ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Control Group ◽  
Mrna Levels ◽  
Model Assessment ◽  
Obese Patients ◽  
Obese Subjects

Context: Zinc-α2 glycoprotein (ZAG) has been proposed as a new candidate in the pathogenesis of obesity, but most of the information stems from studies performed in rodents and in vitro assays. Objective: The main aim of the study was to compare serum levels of ZAG and its expression (mRNA levels and protein) in adipose tissue and the liver between obese and nonobese subjects. The relationship between ZAG and insulin resistance was also explored. Design: This was a case-control study. Setting: The study was conducted at a university referral center. Patients and Methods: Samples of serum, sc adipose tissue (SAT), visceral adipose tissue (VAT), and liver were obtained from 20 obese subjects during bariatric surgery. Samples from 10 nonobese patients matched by age and gender were used as a control group. Serum ZAG levels were determined by ELISA. ZAG mRNA levels were measured by real-time PCR and protein content by Western blot. The effect of insulin on liver production of ZAG was assessed using HepG2 cultures. Results: Serum concentration of ZAG (micrograms per milliliter) was significantly lower in obese subjects (40.87 ± 10.45 vs. 63.26 ± 16.40; P = 0.002). ZAG expression was significantly lower in the adipose tissue (SAT and VAT) and liver of obese patients than in control subjects. Significant negative correlations between body mass index and circulating ZAG (r = −0.65, P &lt; 0.001) as well as between body mass index and mRNA ZAG levels in SAT (r = −0.68, P &lt; 0.001) and VAT were detected (r = −0.64, P &lt; 0.001). No relationship was found between ZAG and homeostasis model assessment for insulin resistance and insulin had no effect on ZAG production in vitro. Conclusion: A down-regulation of ZAG in SAT, VAT, and liver exists in obese patients but seems unrelated to insulin resistance. A downregulation of zinc-α2 glycoprotein in adipose tissue and liver exists in obese patients, and it is unrelated to insulin resistance.

Elevated β2-adrenoceptor protein concentration in adipose tissue from obese subjects is closely related to the body mass index and waist/hip ratio

2003 ◽  
Vol 104 (2) ◽  
pp. 93-102 ◽  
Author(s):  
Mads RASMUSSEN ◽  
Thomas ALMDAL ◽  
Palle BRATHOLM ◽  
Niels Juel CHRISTENSEN
Keyword(s):  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Protein Concentration ◽  
The Body ◽  
Receptor Protein ◽  
Mrna Levels ◽  
Membrane Area ◽  
Waist Hip Ratio ◽  
Obese Subjects

The aim of the present study was to quantify β2-adrenoceptor protein content in adipose tissue during fasting, and to study the relationships between β2-adrenoceptor protein and mRNA levels and changes in metabolites related to lipolysis. Groups of male subjects with a body mass index of <25kg/m2 or >30kg/m2 fasted for 60h. Abdominal subcutaneous fat biopsies were analysed for receptor mRNA levels by reverse transcription–PCR–HPLC. The β2-adrenoceptor protein concentration was measured by Western blotting using fluorescence laser scanning for detection. The β2-adrenoceptor protein concentration per cell (on a DNA basis) was higher in obese subjects (P<0.03). There were highly significant relationships between β2-adrenoceptor protein concentration and both body mass index and waist/hip ratio (P<0.001 for both). Furthermore, there was an inverse relationship between the receptor protein concentration and the serum β-hydroxybutyrate level during fasting (P<0.005). β2-Adrenoceptor protein levels decreased in both groups during fasting, to a similar degree. Basal β2-adrenoceptor mRNA levels were similar in the two groups, but there was a smaller increase in the obese group during fasting (P<0.03). The increased β2-adrenoceptor protein level in obese subjects is likely to be related to the greater plasma membrane area of their adipocytes. The decrease during fasting may be due to increased binding of noradrenaline and subsequent internalization and degradation of the receptor. Elevated levels of less responsive β2-adrenoceptor protein in obese subjects may contribute to the development of obesity.

scholarly journals Correlation of Body Mass Index, Skeletal Muscle, Subcutaneous and Visceral Adipose Tissue in Healthy Adults: A Cross Sectional Study

2021 ◽  
Vol 66 (3) ◽  
pp. 69-76
Author(s):  
NORBERT CSABA LUKÁCS
Keyword(s):  
Skeletal Muscle ◽  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Visceral Adipose Tissue ◽  
Negative Correlation ◽  
Significant Negative Correlation ◽  
The Body ◽  
Cross Sectional ◽  
Visceral Adipose

ABSTRACT. Introduction. Obesity is one of the 21st century major health challenges. Adipose tissue is distributed in different proportions in the human body depending on where it is located in the body. The purpose of the research. This study aims to determine the relationship between body mass index, skeletal muscle, subcutaneous and visceral adipose tissue in case of first year students of Partium Christian University from Oradea. Subjects and methods. The research included a sample group of 112 students. The analysis of the body composition was performed using the method of bioelectrical impedance. Results. The registered data reveal that 23% of the subjects were overweight or obese and 15% had a low percentage of skeletal muscle. Conclusions. In case of both genders there is a significant negative correlation between the percentage of skeletal muscle and subcutaneous adipose tissue and a significant negative correlation between the percentage of skeletal muscle and visceral adipose tissue.

scholarly journals BODY COMPONENT COMPOSITION AND STRESS-INDUCED FEATURES OF LEPTIN SECRETION IN FEMALES WITH VARIOUS BODY MASS INDEX

2020 ◽  
Vol 20 (2) ◽  
pp. 80-89
Author(s):  
L Smelysheva ◽  
E Musikhina ◽  
N Artenyan ◽  
G Kovaleva ◽  
G Kuznetsov
Keyword(s):  
Body Mass Index ◽  
Adipose Tissue ◽  
Body Mass ◽  
Component Composition ◽  
The Body ◽  
Leptin Resistance ◽  
Enzyme Linked Immunosorbent Assay ◽  
Energy Status ◽  
Significant Difference ◽  
Body Component

Aim. The article aims to study the dynamics of the adipose tissue hormone leptin in healthy females with different body component composition and body mass index to assess their energy status under stress. Materials and methods. Based on anthropometry and bioimpedancemetry, three groups of girls were formed: the first group included girls with a BMI of less than 18.5 kg/m2, body mass deficiency (BMD), the second – from 18.5 to 24.9 kg/m2, normal body mass (NBM), the third – with a BMI of more than 24.9 kg/m2, which corresponds to overweight (OvBM). The body component composition was determined by bioimpedancemetry. Plasma leptin concentration was evaluated by enzyme-linked immunosorbent assay both in normal conditions and during emotional stress. Results. In the selected subgroups, a significant difference in the body component composition was found with an increase in the series of BMD → NBM → OvBM. When assessing the level of metabolic processes by the magnitude of the phase angle, it was found that 3.41% of females with BMD showed signs of increased protein catabolism. The stress-induced dynamics of the hormone leptin was evaluated. In normal conditions, the concentration of leptin in blood plasma positively correlated with BMI and depended on the component composition of the body. Conclusion. In persons with BMD, the adipose tissue hormone leptin had a negative dynamics under stress conditions, which was an adequate adaptive physiological response to stress. Females with BMD had a significantly high positive dynamics of leptin, while girls with OvBM did not have significant changes in its concentrations, which can be explained by the development of leptin resistance.

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