J. Hejnova

Effect of hypocaloric diet-induced weight loss in obese women on plasma apelin and adipose tissue expression of apelin and APJ

OBJECTIVE Apelin is a novel adipokine acting on APJ receptor, regulated by insulin and tumor necrosis factor-alpha (TNF-alpha) in adipose tissue (AT). Plasma apelin levels are increased in obese hyperinsulinemic subjects. The aim was to investigate whether the hypocaloric diet associated with weight loss modifies the elevated plasma apelin levels and the expression of apelin and APJ receptor in AT in obese women. DESIGN AND METHODS Fasting plasma levels of apelin and TNF-alpha as well as mRNA levels of apelin and APJ in AT were measured before and after a 12-week hypocaloric weight-reducing diet in 20 obese women (body mass index (BMI) before diet 32.2+/-6.4 kg/m(2)). Twelve healthy women with a BMI of 20.7+/-0.6 kg/m(2) served as reference. RESULTS Plasma levels of apelin and TNF-alpha were higher in obese compared with lean controls. The hypocaloric diet resulted in a significant decrease of BMI to 29.8+/-6.3 kg/m(2), plasma insulin (8.16+/-0.73 to 6.58+/-0.66 mU/l), apelin (369+/-25 pg/ml to 257+/-12 pg/ml), TNF-alpha levels (0.66+/-0.04 pg/ml to 0.56+/-0.04 pg/ml), and AT mRNAs of apelin and APJ. In addition, changes in AT mRNA apelin were related to changes in AT mRNA APJ levels. CONCLUSION The hypocaloric diet associated with weight loss reduces the increased plasma and AT expression of apelin in obese women. This reduced apelin expression in AT could contribute to decreased circulating apelin levels.

Increased lipolysis in adipose tissue and lipid mobilization to natriuretic peptides during low-calorie diet in obese women.

OBJECTIVE: We recently demonstrated that natriuretic peptides (NP) are involved in a pathway inducing lipolysis in human adipose tissue. Atrial NP (ANP) and brain NP (BNP) operate via a cGMP-dependent pathway which does not involve phosphodiesterase-3B inhibition or cAMP. The study was performed to evaluate the effect of ANP on lipid mobilization in obese women and secondly to examine the possible effect of a low-calorie diet (LCD) on the lipolytic response of subcutaneous abdominal fat cells to NP and on the lipid mobilization induced by ANP infusion (1 µg/m2 min for 60 min).SUBJECTS: Ten obese women from 40.5±3.4 y old were selected for this study. Their body weight was 96.4±5.7 kg and their BMI was 35.3±1.7 kg/m2. They received a 2.5–2.9 MJ/day formula diet for 28 days.DESIGN: Before and during the LCD, an adipose tissue biospy was performed for in vitro studies and, moreover, ANP was perfused i.v. to evaluate its lipid mobilizing action in toto and in situ in subcutaneous abdominal adipose tissue (SCAAT) using microdialysis.RESULTS: The lipolytic effects of isoproterenol, ANP, BNP and bromo-cGMP (an analogue of cGMP) on fat cells increased by about 80–100% during LCD. The lipid mobilization during i.v. ANP infusion, assessed by plasma non-esterified fatty acids (NEFA) increase was enhanced during the LCD. However, during LCD, ANP infusion induced a biphasic effect on glycerol concentration in plasma and interstitial fluid of SCAAT; a significant increase was observed in glycerol levels during the first 30 min infusion period, followed by a steady decrease. The concentration of glycerol was lower during the post-infusion period than during the baseline period. This effect was stronger in obese subjects submitted to the LCD with a low-carbohydrate composition. Other plasma parameters were weakly increased (noradrenaline) or not modified (insulin, glucose) by ANP infusion and no difference was found before and during LCD treatment.CONCLUSION: The present study shows that NP are powerful lipolytic agents in subcutaneous fat cells and that both isoproterenol- and NP-induced lipolysis increase during LCD, in obese women. These changes seem to be associated with an improvement of the lipolytic pathway at a post-receptor level. Moreover, i.v. administration of ANP induced a lipid mobilizing effect which was enhanced by a LCD in these objects.

Endurance training changes in lipolytic responsiveness of obese adipose tissue

The aim of this study was to investigate the effect of aerobic exercise training on the lipolytic response of adipose tissue in obese subjects. Thirteen men (body mass index = 36.9 +/- 1.3 kg/m2) were submitted to aerobic physical training on a cycloergometer (30-45 min, 4 days a wk) for 3 mo. Adipocyte sensitivity to the action of catecholamines and insulin was studied in vitro before and after training. Training induced a decrease in the percentage of fat mass (P < 0.05) without changing the body weight. Basal lipolysis and hormone-sensitive lipase activity were significantly decreased after training (P < 0.05). The lipolytic effects of epinephrine, isoprenaline (beta-adrenoceptor agonist), and dobutamine (beta1-adrenoceptor agonist) were significantly increased (P < 0.05) but not those of procaterol (beta2-adrenoceptor agonist). The antilipolytic effects of alpha2-adrenoceptor and insulin were significantly decreased (P < 0.05). Lipolysis stimulation by agents acting at the postreceptor level was unchanged after training. In conclusion, aerobic physical training in obese male subjects modifies adipose tissue lipolysis through an enhancement of beta-adrenergic response and a concomitant blunting of adipocyte antilipolytic activity.The aim of this study was to investigate the effect of aerobic exercise training on the lipolytic response of adipose tissue in obese subjects. Thirteen men (body mass index = 36.9 ± 1.3 kg/m2) were submitted to aerobic physical training on a cycloergometer (30-45 min, 4 days a wk) for 3 mo. Adipocyte sensitivity to the action of catecholamines and insulin was studied in vitro before and after training. Training induced a decrease in the percentage of fat mass ( P < 0.05) without changing the body weight. Basal lipolysis and hormone-sensitive lipase activity were significantly decreased after training ( P < 0.05). The lipolytic effects of epinephrine, isoprenaline (β-adrenoceptor agonist), and dobutamine (β1-adrenoceptor agonist) were significantly increased ( P < 0.05) but not those of procaterol (β2-adrenoceptor agonist). The antilipolytic effects of α2-adrenoceptor and insulin were significantly decreased ( P < 0.05). Lipolysis stimulation by agents acting at the postreceptor level was unchanged after training. In conclusion, aerobic physical training in obese male subjects modifies adipose tissue lipolysis through an enhancement of β-adrenergic response and a concomitant blunting of adipocyte antilipolytic activity.

Endurance training increases the β-adrenergic lipolytic response in subcutaneous adipose tissue in obese subjects

OBJECTIVE: The aim of this study was to assess, by longitudinal follow-up, the influence of aerobic training on the in vivo lipolytic activity of adipose tissue in obese male subjects.SUBJECTS: Eleven obese non-diabetic males, aged 41.5±5.7 7 (range 27–49 y) with body mass index (BMI) 36.5±4.5 kg\m2 (range 29.4–47.1 kg\m2) participated in the study.DESIGN: Subjects took part in a 12-week aerobic training program. Before and after training, microdialysis of abdominal subcutaneous adipose tissue (SCAT) was carried out, using perfusion with graded doses of the β β-adrenergic agonist isoprenaline and a single dose of the phosphodiesterase inhibitor theophylline. In addition, the response of plasma glycerol and free fatty acids (FFAs) to intravenous infusion of graded doses of isoprenaline was tested.RESULTS: The training did not induce significant weight loss and promoted an increase in maximum aerobic capacity (P<0.05). The increase of extracellular glycerol in SCAT in response to isoprenaline perfusion was enhanced after the training (P<0.05), while no change in the response of interstitial glycerol to theophylline action was observed. The training did not elicit a change in the isoprenaline-induced changes of blood flow in adipose tissue. The increases of plasma FFAs and glycerol in response to intravenous isoprenaline infusion, were significantly enhanced after training.CONCLUSION:The present study shows that aerobic training induced an increase in the response of plasma and subcutaneous adipose tissue concentration of glycerol to β-adrenergic stimulation. The effect of an agent acting at the post-receptor level (theophylline) in SCAT was not modified by training.

Dynamic strength training improves insulin sensitivity and functional balance between adrenergic alpha 2A and beta pathways in subcutaneous adipose tissue of obese subjects.

Aims/hypothesisThe aim of this study was to investigate whether dynamic strength training modifies the control of lipolysis, with particular attention paid to the involvement of the antilipolytic adrenergic alpha 2A receptor (ADRA2A) pathway.MethodsTwelve obese men (age: 47.4±2.8 years; BMI: 32.7±0.9) were investigated during a 210-min euglycaemic–hyperinsulinaemic clamp conducted before and after 3 months of dynamic strength training. Before and during the third hour of the clamp, the lipolytic effect of a perfusion of isoproterenol or adrenaline (epinephrine) alone or associated with the ADRA2A antagonist phentolamine was evaluated using the microdialysis method of measuring extracellular glycerol concentration (EGC) in subcutaneous abdominal adipose tissue (SCAAT). In addition, biopsies of SCAAT were carried out before and after training to determine mRNA levelsResultsThe training increased insulin sensitivity in adipose tissue. The decrease of EGC was more pronounced during the clamp conducted after the training period than during the clamp done in pre-training conditions. Before and after the training, catecholamines induced an increase in EGC, the increase being lower during the clamp on each occasion. The isoproterenol-induced increase in EGC was higher after the training. Adrenaline-induced lipolysis was potentiated by phentolamine after but not before the training. There were no training-induced changes in mRNA levels of key genes of the lipolytic pathway in SCAAT.Conclusions/interpretationIn obese subjects, dynamic strength training improves whole-body and adipose tissue insulin responsiveness. It increases responsiveness to the adrenergic beta receptor stimulation of lipolysis and to the antilipolytic action of catecholamines mediated by ADRA2As.

Visfatin expression in subcutaneous adipose tissue of pre-menopausal women: relation to hormones and weight reduction

Background   A novel adipokine, visfatin, was found to be related to adiposity in humans and regulated by a number of hormonal signals. The aim of this study was to investigate the relationships of visfatin expression in adipose tissue with potential regulatory factors such as insulin, testosterone and tumor necrosis factor‐α (TNF‐α) and to elucidate the effect of a diet induced weight reduction on adipose tissue mRNA expression and plasma levels of visfatin.

Post-prandial endothelial dysfunction is ameliorated following weight loss in obese premenopausal women

Summary Background Endothelial dysfunction and postprandial hyperglycemia represent independent risk factors for cardiovascular diseases. Obesity is connected with endothelial impairments; however, it is unclear whether weight loss can modify endothelial function during the postprandial period. The aim of this study was to evaluate endothelial response (post-ischemic forearm blood flow, PIFBF) in a fasted state and following ingestion of 75g glucose before and after very low caloric diet (VLCD). Material/Methods 40 obese premenopausal women (age 39.6±7.8 years, BMI 34.3±3.2 kg/m2) participated in 4-week very low caloric diet (VLCD, 800kcal/day). Before and after VLCD, the baseline blood flow and PIFBF were measured using a mercury strain gauge plethysmography in fasting state as well as 1 hour after ingestion of 75 g glucose. Results Dietary intervention resulted in a 7% weight loss (p<0.05) and a decrease in insulin resistance index HOMA-IR (2.44±1.25 vs. 1.66±0.81, p<0.05). Before VLCD intervention, PIFBF following oral glucose challenge decreased by 8.2±9.1 ml/min/100 g tissue, while after weight loss identical stimulus increased PIFBF by 4.2±8.9 ml/min/100 g tissue (p<0.05). Plasma ICAM-1 and VCAM-1 decreased by 8% and 10%, respectively, throughout the study. Conclusions Postprandial endothelial dysfunction is ameliorated following weight loss in obese women. This finding demonstrates the beneficial effects of weight reduction on atherosclerosis risk.

Use of reversed regulation of work rate intensity by heart rate in testing physical fitness (CHR test)

A method of testing endurance capacity and physical fitness (40‐minute test) based on control of the test work rate by a defined heart rate (clamped heart rate [CHR] test) is proposed. This test was used on 26 men and 19 women with sedentary occupations, about half of whom had regular unorganized sporting activity. A subjects physiologic reaction to a heart rate adjusted work rate and, concomitantly, endurance performance and physical fitness was assessed on the basis of the time course of a changing intensity of work rate necessary to maintain a CHR. Auxiliary indices of the test, some of them marking a significant difference between subgroups with different levels of physical fitness, were calculated. Average power output related to weight and to the utilized portion of circulation capacity was determined as the basic criterion of physical fitness. A comparison between the indices revealed that the better a persons physical fitness, the less frequent was a reduction in work rate necessary to maintain ...