Ghrelin does not regulate the GH response to insulin-induced hypoglycaemia in children but could be involved in the regulation of cortisol secretion

OBJECTIVE

Ghrelin activates the growth hormone secretagogue receptor GHS-R. It strongly stimulates GH secretion and has a role in energy homeostasis. The relationship between plasma ghrelin and cortisol levels during insulin-induced hypoglycaemia in prepubertal and pubertal children has not yet been investigated. The aim of the present study was to establish whether insulin-induced hypoglycaemia stimulates ghrelin secretion and whether changes in ghrelin concentrations are related to changes in GH and cortisol in children.

DESIGN AND PATIENTS

We studied a group of 20 children and adolescents (five girls, 15 boys, mean age 10.8 +/- 3.7 years) undergoing insulin tolerance tests (ITTs) for clinical investigation of GH deficiency.

MEASUREMENTS

Stimulation tests were performed to investigate the relationship between ghrelin, GH, cortisol and glucose levels according to age and pubertal stage by determining the ghrelin profiles during insulin-induced hypoglycaemia (at 0, 60 and 120 min).

RESULTS

Ghrelin was significantly and inversely related to body weight, height, body mass index (BMI) and age of children (P < 0.05). Significant changes in ghrelin levels (P = 0.00013) were found after the insulin bolus, with a decline at 60 min and an increase to baseline values at 120 min. Changes in cortisol levels were negatively correlated with changes in ghrelin at 60 min (r = -0.59, P = 0.004) and at 120 min (r = -0.605, P = 0.003).

CONCLUSIONS

This study shows that ghrelin might not regulate the GH response to insulin-induced hypoglycaemia in prepubertal and pubertal children. A role for ghrelin in the regulation of cortisol secretion can be hypothesized concerning the negative correlation between changes in ghrelin and cortisol. Furthermore, the results imply that ghrelin secretion is age dependent and is a function of growth.

Oktreotidszintigraphie zur Diagnose der aktiven endokrinen Orbitopathie

PURPOSE

In this study the diagnostic accuracy of orbital octreotide uptake in patients with presumed active Grave's ophthalmopathy (GO) was evaluated.

PATIENTS AND METHODS

A prospective study of 23 patients suffering from GO was carried out. Single photon emission computed tomography (SPECT) images were obtained 4 h after iv injection of 3 mCi 111 indium octreotide. The results were correlated with the patients clinical state during a follow-up of 17.5+/-6 months.

RESULTS

Octreotide scintigraphy was positive in 15 and negative in 8 cases, 12 patients with positive octreotide scintigraphy underwent immunosuppressive treatment and showed a clinically positive response with regression of symptoms. In three cases the patients refused immunosuppressive treatment. Patients with negative pathologic orbital octreotide uptake did not undergo any treatment.

CONCLUSION

Octreotide scintigraphy is a useful tool to determine the activity state of Graves' ophthalmopathy. Since Graves' ophthalmopathy must be treated in the active phase, octreotide scintigraphy should be performed in subacute cases to facilitate the indications for immunosuppressive treatment.

Amplitude coded-colour Doppler sonography in paediatric renal disease

The aim of our study was to assess the ability of amplitude coded-colour Doppler sonography (ACDS) to depict altered perfusion in paediatric renal disease in a prospective study. Colour Doppler sonography (CDS) and ACDS examinations were performed in 180 renal units (90 patients; age range newborn to 16 years) with unilateral or bilateral renal disease (e.g. reflux nephropathy, renal scars, end-stage renal disease, ureteropelvic junction obstruction, urinary tract infection, renal failure, haemolytic uraemic syndrome, nephrotic syndrome, systemic lupus erythematosus (LE), renal biopsy, congenital dysplasia, tumour/infiltration). The ACDS results were compared with scintigraphy or CT as well as to clinical findings. Amplitude colour-coded Doppler sonography accurately demonstrated normal vasculature in 49 of 51 healthy kidneys (= 96%); 3 healthy kidneys could not be evaluated due to motion/artefacts. In 39 of 43 kidneys with focally altered perfusion ACDS could be performed and correctly depicted focally impaired vasculature/perfusion in 35 kidneys (= 89.7%). Seventy-three of 83 kidneys with diffusely impaired perfusion could be evaluated by ACDS and altered pattern was correctly depicted in 58 kidneys (= 79.4%), with an overall percentage of agreement of 87.1%. Amplitude CDS appears to be useful in infants and children. Compared with CDS it improves visualisation of especially focally impaired vasculature/perfusion and should be considered a valuable adjunct to conventional investigations.

Vitamin E kinetics in smokers and nonsmokers

Does cigarette smoking increase vitamin E utilization in vivo? A trial was carried out in 6 smokers and 5 nonsmokers of comparable ages and serum lipids. Subjects consumed 75 mg each d(3)-RRR and d(6)-all rac-alpha-tocopheryl acetates (natural and synthetic vitamin E, respectively) daily for 7 d with a standardized breakfast. Fasting blood samples were drawn on days -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 14, 21 (negative days indicate supplementation). In both groups, plasma d(3)-alpha-tocopherol concentrations were approximately double of d(6)-alpha-tocopherol. At day 0, the %d(3) alpha-tocopherols (d(3)-alpha-tocopherol/total-alpha-tocopherol x 100) were similar in both smokers and nonsmokers. Subsequently, there was a trend toward a faster exponential disappearance of the plasma %d(3) alpha-tocopherol in smokers compared with nonsmokers (0.30 +/- 0.04 compared with 0.24 +/- 0.05, p =.0565). The calculated %d(3) half-lives were 55.6 +/- 7.4 h in smokers and 72.1 +/- 17.3 h in nonsmokers (p =.0630). By day 21, the %d(3) in smokers had decreased to 1.4% +/- 0.3% while it was 2.2% +/- 0.7% (p =.0418) in the nonsmokers. These data suggest that smoking increases plasma vitamin E disappearance, but further studies are needed to confirm this finding and to assess its cause.

The effects of changes in body mass and subcutaneous fat on the improvement in metabolic risk factors in obese children after short-term weight loss

The pattern of subcutaneous fat (SAT) is related to metabolic risk factors in obese children. Because weight loss improves the risk-factor profile, we sought to determine whether changes in SAT or SAT-pattern contribute to the improvement in the risk-factor profile after 3 weeks of a low-calorie diet and physical activities. In 22 obese boys (mean age, 11.9 years) and 40 obese girls (mean age, 12 years), fat mass (by means of impedance) and fat distribution (waist and hip circumference) were assessed. The thickness of 15 different subcutaneous adipose tissue layers (SAT-layers) was measured using a Lipometer (Moeller Messtechnik, Graz, Austria). SAT and SAT-pattern (arm-SAT, trunk-SAT, leg-SAT) were calculated. Blood samples were taken for the determination of insulin, glucose, triglycerides, and cholesterol. After 3 weeks, fat mass, waist and hip circumference, SAT, arm-SAT, trunk-SAT (all P <.0001), and leg-SAT (P <.01) were reduced. Besides glucose, metabolic parameters were lowered (all P <.001) but changes in metabolic parameter were interrelated in boys and girls. Age- and sex-adjusted regression revealed that changes in body mass contributed to the variability in changes of insulin (adjusted R(2) =.15, P =.0015). For the change in triglycerides, changes in cholesterol together with subtle alterations in glucose and changes in leg-SAT were found to be the main determinants (adjusted R(2) =.587, P <.0001). The results indicate that the change in the atherogenic and metabolic risk factor profile is largely independent from the concomitant loss in SAT. The reduction in body mass explained only a small part of the variability in changes of insulin, but leg-SAT might participate in the lowering of triglycerides, especially in boys. The contribution of SAT-pattern to the risk factor profile is an issue that needs further investigation.

Changes in serum interleukin-6 concentrations in obese children and adolescents during a weight reduction program

OBJECTIVE

To investigate the effect of short term energy restriction combined with physical activity on serum concentrations of Interleukin-6 (IL-6) in obese children and adolescents.

DESIGN

Longitudinal intervention study of 3.8-5 MJ daily with exercise.

SUBJECTS

Forty-nine white obese children and adolescents (31 girls, age 11.9+/-1.8 y; 18 boys, age 11.6+/-1.7 y).

MEASUREMENTS

Indexes of obesity, IL-6, leptin, estradiol, systolic and diastolic blood pressure, heart rate at baseline and after 3 weeks.

RESULTS

All determined parameters decreased significantly during the 3 week program (IL-6: 3.9+/-4.7 vs 2.0+/-2.2 pg/ml; P<0.05). Body mass index (BMI) fat mass, percentage fat mass (indexes of obesity), and leptin were not related to IL-6 before the program. In contrast, IL-6 concentrations correlated significantly with indexes of obesity and leptin after weight loss. IL-6 concentrations did not correlate with estradiol, systolic and diastolic blood pressure, and heart rate. Changes in IL-6 concentrations correlated significantly with changes in BMI (r=0.25, P<0.05).

CONCLUSION

An improved body composition induced by restriction of energy intake and increase in physical activity is associated with more favorable serum concentrations of IL-6 in obese children and adolescents.

Determinants of homocysteine during weight reduction in obese children and adolescents

Plasma homocysteine levels have been shown to be associated with indexes of obesity and insulin resistance in obese children and adolescents. We, therefore, investigated the contribution of changes in body composition, markers of insulin resistance, folate, and vitamin B(12) to changes in homocysteine during a weight reduction program in obese children and adolescents. Thirty-seven obese white girls (mean SD; age, 12 +/- 1.8 years, body mass index [BMI], 26.9 +/- 5.25) and 19 obese white boys (age, 11.9 +/- 1.7 years; BMI, 26.2 +/- 5.2) were investigated for body composition, fasting total plasma homocysteine (tHcy), insulin, C-peptide, folate, and vitamin B(12) before and after a 3-week weight reduction program including physical activities. During weight reduction BMI, fat mass (FM), percentage fat mass, insulin, and C-peptide decreased significantly, whereas homocysteine and vitamin B(12) showed a significant increase. Folate and lean body mass (LBM) remained unchanged. tHcy concentration before weight reduction was a function of age, folate, and C-peptide, whereas tHcy concentration after weight reduction was a function of folate and baseline LBM. Changes in tHcy during weight reduction correlated significantly with baseline LBM and were related inversely to changes in LBM during weight reduction. Children who increased LBM showed lower increases in tHcy compared with children who lost LBM. In multiple linear regression analysis, only baseline LBM contributed independently and significantly to changes in tHcy. Our study suggests that LBM has a significant impact on tHcy metabolism during weight reduction.

Interrelationship between estimates of adiposity and body fat distribution with metabolic and hemostatic parameters in obese children

Adiposity in childhood is often associated with metabolic abnormalities and accompanied by a dysregulation of the coagulation and fibrinolytic systems. We studied the interrelationship of metabolic and hemostatic parameters and explored their relationship with measures of adiposity and fat distribution in obese children. In 34 obese boys (mean age, 11.7 years) and 57 obese girls (12.1 years), blood samples were determined for insulin, glucose, triglycerides, fibrinogen, plasminogen activator inhibitor-1 (PAI-1), and tissue-type plasminogen activator-antigen (tPA-Ag). Body composition was assessed by means of impedance. Waist (Wc) and hip circumference were measured. The thickness of subcutaneous adipose tissue-layers (SAT-layers) was measured at 15 different body sites (from 1-neck to 15-calf) by means of the optical device, Lipometer. Overall subcutaneous fatness (SAT) was calculated and SAT-distribution was estimated by means of factor analysis. Significant correlations were found between different measures of adiposity and Wc with metabolic parameters. Fibrinogen was mainly associated with upper body subcutaneous fatness (factor 1) in boys. In girls, hemostatic parameters were associated with nearly all measures of adiposity and also with factor 1 and SAT. Regression analysis showed that factor 1 together with PAI-1 (both P <.0001) contribute to fibrinogen (adjusted [adj], R(2) =.30). PAI-1 together with trigylcerides (both P <.0001) and age (P <.04) were main determinants for tPA-Ag (adj, R(2) =.41). tPA-Ag (P <.0001) together with glucose (P <.001, negative slope), fibrinogen (P <.001, negative slope), and percentage fat mass (%FM) (P <.01) contributed to PAI-1 (adj, R(2) =.54). These results favor the concept of an interrelationship between metabolic and hemostatic parameters resulting from increased adiposity, perhaps influenced by pubertal development of children. Although upper body subcutaneous fatness was found to be a main correlate of metabolic and hemostatic parameters, it remains to be investigated whether this type of subcutaneous fat distribution is involved in the expression of metabolic and hemostatic risk factors and participates in the dysregulation of the hemostatic system in the state of childhood obesity.

Subcutaneous adipose tissue layers as a stable correlate of leptin in response to short term energy restriction in obese girls

AIMS

We studied the relationship of subcutaneous adipose tissue layers (SAT-layers) measured at 15 specified body sites with leptin before and after a weight loss program for three weeks.

SUBJECTS AND METHODS

In 70 obese girls, SAT-layers were measured by means of the optical device, lipometer. Fat mass (FM) was estimated by means of bioelectrical impedance.

RESULTS

At the beginning of the study, all estimates of adiposity, insulin, and SAT-layers from the upper body (from 1-neck to 6-lateral chest) were correlated to leptin at a P-value of<0.0001. Percentage FM together with SAT-layer 4-upper back and insulin explained 75% of the variation in leptin (P<0.0001). After three weeks, estimates of adiposity and leptin were reduced (all P<0.0001). Most SAT-layers were reduced, but SAT-layers 8-lower abdomen and 9-lower back were significantly increased. Changes in leptin were best explained by initial leptin, but percentage change (Delta) in insulin, Delta SAT-layer 1-neck, and Delta SAT-layer 3-biceps contributed to the Delta leptin (adj. r(2)=0.47, P<0.0001). In the weight-reduced state, circulating leptin was best explained by three SAT-layers and insulin (adj. r(2)=0.67, P<0.0001).

DISCUSSION

The results suggest that Delta changes in leptin are attributable to changes in the endocrine state and subcutaneous fat, and SAT-layers may serve as a stable correlate of leptin in the weight-reduced state.

Effects of weight loss on leptin, sex hormones, and measures of adiposity in obese children

Adipose tissue influences steroid conversion by paracrine and autocrine mechanisms. Leptin is secreted by adipocytes and influenced by sex hormones and adiposity. Short-term weight loss in the treatment of childhood obesity reduces leptin and adipose tissue. We therefore asked, Do alterations in sex hormones occur owing to weight loss? and can these alterations be explained by changes in fat mass or sc fat and are alterations in sex hormones directly related to the fall in leptin? Twenty obese boys and 40 obese girls were studied before and after 3 wk of low-calorie diet and physical activity. The weight loss program significantly lowered fat mass, abdominal fat distribution, sc fat (all p < 0.0001), leptin, insulin, and estradiol (all p < 0.0001) but not testosterone. Changes in leptin were related to changes in body mass and to changes in fat mass in boys. In girls, changes in leptin were related to changes in sc fatness and also to changes in insulin. In boys, the reduction in sc fat was positively correlated to changes in testosterone (r = 0.54; p < 0.01) and inversely related to the fall in estradiol (r = -0.41; p < 0.05). In girls, changes in testosterone (r = 0.33; p < 0.05) and in estradiol (r = 0.40; p < 0.01) were related to changes in insulin. Stepwise regression showed that initial leptin was the best determinant for the fall in leptin (adjusted R2 = 0.87; p < 0.0001). The results show that alterations in sex hormones are related to changes in certain fat depots in boys whereas in girls changes in insulin might participate in changes in sex hormones. A greater fall in leptin owing to short-term weight loss is not associated with greater alterations in sex hormones and initial leptin is the best determinant to explain the variability in changes in leptin. The possibility of sex differences in changes in sex hormones secondary to the reduction in fatness warrants further study.

Pancreatitis-associated protein (PAP) in patients with pancreatic cancer

BACKGROUND

Pancreatitis-associated protein (PAP) is known as a marker for pancreatitis and cystic fibrosis. The aim of our study was to evaluate PAP in patients with pancreatic cancer, to assess its correlation to the extent of the disease and to compare it to CA19-9.

PATIENTS AND METHODS

This prospective study comprised 75 individuals. Thirty had pancreatic cancer, 30 were healthy controls and 15 had benign lesions of the pancreas. PAP was determined by enzyme-linked immunosorbent assay. Statistical analysis was by Wilcoxon test and Spearman correlation coefficients.

RESULTS

As compared to healthy individuals and using a cut-off of 18 micrograms/l corresponding to a sensitivity of 90%, the specificity of PAP for pancreatic cancer was 82.8%. PAP elevation in cancer patients could not be explained by concomitant pancreatitis (p = 0.649). PAP did not show correlation to tumour size (p = 0.14), T-stages (p = 0.706) or tumour grading (p = 0.105), but was significantly correlated to the overall extent of the disease according to the UICC stages (p = 0.002). No correlation between PAP and CA19-9 was seen. Jaundice was not found to influence PAP values (p = 0.4).

CONCLUSION

Elevation of PAP in patients with pancreatic cancer is not merely explainable by concomitant pancreatitis, but seems to be due to increased PAP production by the cancer cells and is also correlated to tumour load as expressed by the UICC stages.

The influence of weight loss on fibrinolytic and metabolic parameters in obese children and adolescents

We studied i) whether short-term weight loss alters plasminogen activator inhibitor-1 antigen (PAI-1-Ag) and tissue-type plasminogen activator antigen (tPA-Ag) in obese children, and ii) whether changes in body composition and/or abdominal adiposity are responsible for changes in PAI-1 and tPA-Ag. 20 obese boys (mean age 11.9 yr) and 40 obese girls (mean age 12 yr) were studied before and after three weeks of low-caloric diet and physical activity. Body composition was assessed by means of bioelectrical impedance, and the waist-to-hip ratio (WHR) was measured. Blood samples were determined for insulin, glucose, triglycerides, PAI-1-Ag, tPA-Ag, and the fasting insulin resistance index (FIRI) was calculated. Boys had a greater WHR, higher levels of glucose, and a slightly greater FIRI than girls. Estimates of adiposity, insulin, and triglycerides were correlated with PAI-1 and tPA-Ag. WHR was significantly correlated with fibrinolytic parameters only in girls. Insulin and tPA-Ag contributed to PAI-1 (adj. R2 = 0.36, p <0.0001), whereas percentage fat mass and triglycerides contributed to tPA-Ag (adj. R2 = 0.469, p <0.0001). The weight loss program significantly reduced adiposity, abdominal adiposity, and lowered fibrinolytic and metabolic parameters. Initial levels of PAI-1 and changes in body mass contributed to the fall in PAI-1 (adj. R2 = 0.18, p = 0.0016) and initial levels of tPA-Ag contributed significantly to changes in tPA-Ag (adj. R2 = 0.57, p <0.0001). The results suggest that changes in fibrinolytic parameters are associated with the loss in body mass but can occur independently of a concomitant reduction in fatness. Although initial PAI-1 and tPA-Ag predict the changes of these fibrinolytic parameters, the results do not exclude the possibility that the improvement in metabolic state and changes in unmeasured parameters related to physical activity and low-caloric diet could have influenced our findings.

Insulin and insulin resistance index are not independent determinants for the variation in leptin in obese children and adolescents

Recent findings have questioned the independent influence of insulin on leptin. We studied whether insulin contributes to leptin in obese children, independent of confounding parameters, such as total adiposity, fasting insulin resistance index, and fat free mass. In 100 obese boys and 103 obese girls, blood levels of leptin, insulin, glucose, and triglycerides were determined. The fasting insulin resistance index (FIRI) was calculated, and body composition was assessed by means of impedance. Leptin and glucose were higher in girls, and all estimates of adiposity were significantly associated with leptin. However, when adjusted for adiposity, the relationship between insulin and leptin, and also between FIRI and leptin, remained significant in boys and girls (p<0.05). Although several regression models were tested, neither insulin nor FIRI were found to contribute significantly and independently to leptin. BMI together with triglycerides and FFM were the main determinants for the variation in leptin in boys (adj. R2=0.46, p<0.0001). In girls, BMI explained a great magnitude of the variation in leptin (adj. R2=0.60, p<0.0001). These findings indicate that in the state of childhood and adolescent obesity, total adiposity but not insulin or insulin resistance index is the main determinant for leptin. In contrast to obese girls, the fat free mass and triglycerides contribute significantly to the variation in leptin in obese boys. The biological significance for these findings should be elucidated in longitudinal studies.