Ghrelin and PYY levels in adolescents with severe obesity: effects of weight loss induced by long-term exercise training and modified food habits.

This study investigated (a) changes in ghrelin and peptide YY (PYY) concentrations during a weight reduction programme and (b) baseline ghrelin and PYY levels as predictors of weight loss in 32 severely obese adolescents (BMI z score = 4.1). Subjects spent an academic year in an institution for childhood obesity. Fasting ghrelin and PYY, leptin, insulin levels and insulin resistance were measured at baseline (month 0) and during the programme (months 3, 6, 9). In addition, 15 normal-weight teenagers served as reference for the baseline assessments. At baseline, obese teenagers had lower ghrelin and PYY concentrations than normal-weight adolescents (P < 0.05). Moreover, they showed significantly higher leptin, insulin levels and homeostasis model assessment (HOMA) (P < 0.0001). During the lifestyle modification, there was a significant decrease in body weight among obese teenagers, associated with an increase in ghrelin (apparent from month 6; P < 0.05), a decrease in leptin (from month 3; P < 0.05) and a decrease in insulin and HOMA (from month 3; P < 0.0001), without any significant change in PYY. Anthropometrical changes were correlated neither with baseline ghrelin levels nor with changes in ghrelin and PYY after the lifestyle modification. However, higher baseline PYY tended to correlate with greater anthropometrical changes (P < 0.1). In adolescents with severe obesity, a long-term combination of supervised aerobic exercises and a balanced diet led to weight reduction and increased ghrelin concentrations, without any change in PYY concentrations. Moreover, baseline PYY concentrations might be considered as predictors of weight loss.

Elevated adiponectin serum levels in women with systemic autoimmune diseases.

Adipose tissue produces a wide range of proteins that may influence the immune system. In this study, we assessed the serum levels of leptin, adiponectin, and ghrelin, in association with the measurements of body composition, in 15 female patients with various autoimmune diseases (systemic lupus erythematosus, primary Sjögren's syndrome, sarcoidosis, mixed connective tissue disease, vasculitis, CREST syndrome, and polymyositis) and in 15 healthy female controls. There were no statistically significant differences between the patients and controls with regard to serum leptin, serum ghrelin, global fat mass, adiposity, and fat mass in the android or gynoid regions, whereas serum adiponectin levels were higher in patients than controls (16.3 ± 1.6 µg/mL versus 9.7 ± 0.6 µg/mL; P = .01). As adiponectin is known to exhibit potent anti-inflammatory properties, a high adiponectinemia in patients with systemic autoimmune disease may mitigate the inflammatory response. However, the precise consequences of these elevated serum adiponectin levels on the metabolic syndrome development and atherosclerotic cardiovascular risk in this patient population still needs to be determined.

Adipose tissue, serum adipokines, and ghrelin in patients with ankylosing spondylitis.

Adipokines such as leptin and adiponectin are involved in the regulation of inflammation. Ghrelin, a gastric peptide playing a role in the appetite regulation, possesses anti-inflammatory properties. In this study, we evaluated the circulating levels of adipokines (leptin as potential proinflammatory and adiponectin as anti-inflammatory marker) and ghrelin and the fat mass in patients with ankylosing spondylitis (AS). Serum leptin, adiponectin, and ghrelin were evaluated in 53 AS patients with active disease (mean Bath Ankylosing Spondylitis Disease Activity Index >40) and 35 controls. Fat and lean masses were determined using dual-energy x-ray absorptiometry. Fat and lean masses did not differ between patients and controls. Ankylosing spondylitis patients had lower leptin levels compared with controls, even after adjustment for fat mass (AS vs controls: leptin, 7.6 +/- 1.3 ng/mL vs 10.3 +/- 1.5 ng/mL; leptin [in nanograms per milliliter]/fat mass [in kilograms], 0.28 +/- 0.04 vs 0.44 +/- 0.04; P = .006 and P = .0003, respectively). Serum adiponectin did not differ between patients and controls, whereas circulating ghrelin was higher in AS patients (1354.6 +/- 70.5 pg/mL vs 1008.0 +/- 82.5 pg/mL; P = .001). However, all these results were significant only for male patients. No correlation was found between leptin and adiponectin, and erythrocyte sedimentation rate, C-reactive protein levels, tumor necrosis factor alpha, or Bath Ankylosing Spondylitis Disease Activity Index. Ankylosing spondylitis patients had no changes in fat mass. Leptin production was reduced in contrast with normal levels of adiponectin. These adipokine results, together with high serum ghrelin levels, may influence the inflammatory response in AS.

Conditions of autonomic reciprocal interplay versus autonomic co-activation: effects on non-linear heart rate dynamics.

The present study was aimed at investigating the autonomic nervous system influences on the fractal organization of human heart rate during sympathovagal interactions, with special emphasize on the short-term fractal organization in heart rate variability (HRV), as assessed by the scaling exponent (alpha(1)) of the detrended fluctuation analysis. Linear and non-linear HRV analyses were used to study the sympathetic and vagal modulation of heart rate in ten healthy men (mean +/- SEM; age 26 +/- 1 years) during conditions of 1) increased sympathetic activity and vagal withdrawal (head-up tilt), 2) decreased sympathetic activity and increased vagal outflow (thermoneutral upright head-out water immersion, WIn), and 3) simultaneous activation of the two arms of the autonomic nervous activity (upright head-out immersion in cold water, WIc). Hemodynamic and linear HRV results were consistent with previous reports during similar physiological conditions. alpha(1) increased significantly during head-up tilt (from 0.71 +/- 0.13 supine to 0.90 +/- 0.15 upright) and WIn (0.86 +/- 0.10) and was significantly decreased during WIc (0.61 +/- 0.15). Thus, alpha(1) increased when the cardiac autonomic interplay was altered in a reciprocal fashion, whatever the direction of the balance change. Conversely, alpha(1) decreased during the concomitant activation of both vagal and sympathetic activities. The results of linear analysis were necessary to precisely define the direction of change in autonomic control revealed by an increase in alpha(1), while the direction of change in alpha(1) indicated whether an increased vagal activity is coupled with a decreased or increased sympathetic activation. Using both linear and non-linear analysis of HRV may increase the understanding of changes in cardiac autonomic status.

Homocysteine, nutritional status and insulin in renal transplant recipients.

BACKGROUND: Hyperhomocysteinemia is an independent risk factor for the development of cardiovascular conditions in chronic stable renal-transplant recipients (RTR). Major determinants of plasma total homocysteine (tHcy) in RTR are renal function and folate levels. The data dealing with the possible regulation of the tHcy metabolism by insulin and nutritional status is conflicting in non-transplant populations. METHODS: We examined the relationship between tHcy, insulin and nutritional status in 103 chronic, stable RTR. Demographic, clinical, and biochemical parameters were assessed for each patient. RESULTS: Mean tHcy was 19.7+/-9.2 micro mol/l (range 8.6-53). The tHcy was strongly related to creatinine clearance (r=0.55, P<0.0001). Fasting tHcy levels were negatively related to folate concentrations (r=-0.32, P=0.01). There was a positive relationship between tHcy and LDL-cholesterol (r=0.34, P=0.03) and a significant negative correlation between tHcy and insulin (r=-0.38, P=0.01). Fasting tHcy concentrations were significantly higher in the lower quartile of insulin concentration than in the upper quartile (27.7+/-12.7 vs 15.9+/-9.5, P=0.01). In multivariate analysis, tHcy was associated with serum creatinine (P=0.001), insulin (P=0.02) and folate concentration (P=0.03). Patients with the highest IGF-1 concentration had lower tHcy than patients with the lowest IGF-1 concentration (16.8+/-5.7 vs 23.3+/-11 micro mol/l, P=0.01). CONCLUSION: We observed an inverse relationship between insulin and tHcy in chronic, stable RTR.