Resistin, visfatin, leptin and omentin are differently related to hormonal and metabolic parameters in growth hormone-deficient children

Gender-specific soluble α-klotho levels as marker of GH deficiency in children: a case-control study

PURPOSE

To evaluate circulating soluble α-klotho (sαKL) levels in GHD children before and after 12 months of GH treatment (GHT).

METHODS

Auxological and basal metabolic parameters, oral glucose tolerance test for glucose and insulin levels, insulin sensitivity indices and klotho levels were evaluated before and after 12 months of follow-up in 58 GHD children and 56 healthy controls.

RESULTS

At baseline, GHD children showed significantly lower growth velocity standard deviation score (SDS) (p < 0.001), bone/chronological age ratio (p < 0.001), GH peak and area under the curve (AUC) after arginine test (ARG) (both p < 0.001) and glucagon stimulation test (GST) (p < 0.001 and 0.048, respectively), IGF-1 (p < 0.001), with higher BMI (SDS) (p < 0.001), WC (SDS) (p = 0.003) and sαKL (p < 0.001) than controls. After 12 months of GHT, GHD children showed a significant increase in height (SDS) (p < 0.001), growth velocity (SDS) (p < 0.001), bone/chronological age ratio (p < 0.001) IGF-1 (p < 0.001), fasting insulin (p < 0.001), Homa-IR (p < 0.001) and sαKL (p < 0.001) with a concomitant decrease in BMI (SDS) (p = 0.002) and WC (SDS) (p = 0.038) than baseline. At ROC curve analysis, we identified a sαKL cut-off to discriminate controls and GHD children of 1764.4 pg/mL in females and 1339.4 pg/mL in males. At multivariate analysis, the independent variables significantly associated with sαKL levels after 12 months of GHT were the oral disposition index (p = 0.004, β = 0.327) and IGF-1 (p = 0.019, β = 0.313).

CONCLUSIONS

Gender-related sαKL may be used as a marker of GHD combined to GH and IGF-1. Insulin and IGF-1 are independently associated with sαKL values after 12 months of GHT.

The "Adipo-Cerebral" Dialogue in Childhood Obesity: Focus on Growth and Puberty. Physiopathological and Nutritional Aspects

Overweight and obesity in children and adolescents are overwhelming problems in western countries. Adipocytes, far from being only fat deposits, are capable of endocrine functions, and the endocrine activity of adipose tissue, resumable in adipokines production, seems to be a key modulator of central nervous system function, suggesting the existence of an “adipo-cerebral axis.” This connection exerts a key role in children growth and puberty development, and it is exemplified by the leptin–kisspeptin interaction. The aim of this review was to describe recent advances in the knowledge of adipose tissue endocrine functions and their relations with nutrition and growth. The peculiarities of major adipokines are briefly summarized in the first paragraph; leptin and its interaction with kisspeptin are focused on in the second paragraph; the third paragraph deals with the regulation of the GH-IGF axis, with a special focus on the model represented by growth hormone deficiency (GHD); finally, old and new nutritional aspects are described in the last paragraph.

Running wheel access fails to resolve impaired sustainable health in mice feeding a high fat sucrose diet

Diet and physical activity are thought to affect sustainable metabolic health and survival. To improve understanding, we studied survival of mice feeding a low-fat (LF) or high-saturated fat/high sugar (HFS) diet, each with or without free running wheel (RW) access. Additionally several endocrine and metabolic health indices were assessed at 6, 12, 18 and 24 months of age. As expected, HFS feeding left-shifted survival curve of mice compared to LF feeding, and this was associated with increased energy intake and increased (visceral/total) adiposity, liver triglycerides, and increased plasma cholesterol, corticosterone, HOMA-IR, and lowered adiponectin levels. Several of these health parameters improved (transiently) by RW access in HFS and LF fed mice (i.e., HOMA-IR, plasma corticosterone), others however deteriorated (transiently) by RW access only in HFS-fed mice (i.e., body adiposity, plasma resistin, and free cholesterol levels). Apart from these multiple and sometimes diverging health effects of RW access, RW access did not affect survival curves. Important to note, voluntary RW activity declined with age, but this effect was most pronounced in the HFS fed mice. These results thus challenge the hypothesis that voluntary wheel running can counteract HFS-induced deterioration of survival and metabolic health.

Circulating Irisin Levels in Children With GH Deficiency Before and After 1 Year of GH Treatment

PURPOSE

To evaluate circulating irisin levels in children with GH deficiency (GHD) and any relation with clinical and metabolic parameters.

PATIENTS

Fifty-four prepubertal children (mean age, 7.4 ± 0.8 years) with idiopathic GHD treated with GH for at least 12 months and 31 healthy short children as control subjects.

METHODS

Body height, body mass index (BMI), waist circumference (WC), IGF-I, HbA1c, lipid profile, fasting and after-oral glucose tolerance test glucose and insulin, insulin sensitivity indices, and irisin levels were evaluated at baseline and after 12 months of GH replacement (GHR).

RESULTS

At baseline, children with GHD, in addition to having lower growth velocity (P < 0.001), GH peak after stimulation tests (both P < 0.001), and IGF-I (P < 0.001), showed significantly lower irisin (P < 0.001) and higher BMI (P < 0.001) and WC (P = 0.001), without any difference in metabolic parameters, than control subjects. After GHR, children with GHD showed a significant increase in height (P < 0.001), growth velocity (P < 0.001), IGF-I (P < 0.001), fasting glucose (P = 0.002) and insulin (P < 0.001), homeostasis model assessment estimate of insulin resistance (P < 0.001), and irisin (P = 0.005), with a concomitant decrease in BMI (P = 0.001) and WC (P = 0.003). In multivariate analysis, the independent variables significantly associated with irisin were BMI (P = 0.002) and GH peak (P = 0.037) at baseline and BMI (P = 0.005), WC (P = 0.018), and IGF-I (P < 0.001) during GHR.

CONCLUSIONS

We report that GHR leads to an increase in irisin levels, strongly related to a decrease in BMI and WC, and to an increase in IGF-I; these changes are among the main goals of GHR. These data confirm the favorable effects of GHR in children.

Anti-Inflammatory and Pro-Inflammatory Adipokine Profiles in Children on Vegetarian and Omnivorous Diets

Adipose tissue is a highly active endocrine organ that secrets many pro-inflammatory as well anti-inflammatory adipokines. The aim of the study was to assess serum adipokine profile in prepubertal vegetarian and omnivorous children. Sixty-two children on a vegetarian diet and fifty-five children on an omnivorous diet, aged 5 to 10 years, were studied. Dietary assessment was performed using a nutritional software program. Body composition was measured by dual-energy X-ray absorptiometry. Serum concentrations of adipokines: leptin, soluble leptin receptor (sOB-R), adiponectin (total and high molecular weight), resistin, visfatin, vaspin, and omentin were determined by immunoenzymatic assays. Both studied groups of children were comparable in terms of age, weight, height, body mass index, and body composition. Vegetarians had a lower (p = 0.017) leptin/sOB-R ratio and lower serum concentrations of resistin (p = 0.051), compared with omnivores. Average levels of other adipokines did not differ between both groups of children. However, we observed significantly higher ratios of anti-inflammatory to pro-inflammatory adipokines: adiponectin/leptin 0.70 (0.37–0.93) vs 0.39 (0.28–0.74), p = 0.005, and omentin/leptin 0.40 (0.23–0.83) vs. 0.33 (0.15–0.48), p = 0.011 in vegetarians compared with omnivores. A well-planned vegetarian diet might beneficially affect the adipokine profile and inflammatory status expressed by the ratios of anti-inflammatory to pro-inflammatory adipokines in prepubertal children.

The metabolic outcomes of growth hormone treatment in children are gender specific

OBJECTIVE

To evaluate the impact of gender on the clinical and metabolic parameters in prepubertal growth hormone deficiency (GHD) children at diagnosis and during GH treatment (GHT).

DESIGN

The data of 105 prepubertal children (61 males, 44 females, mean age 6.8 ± 0.7 years) affected by idiopathic GHD were retrospectively evaluated.

METHODS

Body height, BMI, waist circumference (WC), IGF-I, HbA1c, lipid profile, fasting and after-OGTT glucose and insulin levels, insulin sensitivity and secretion indices were evaluated at baseline and after 24 months of GHT.

RESULTS

At baseline, no significant difference was found in all clinical, hormonal and metabolic parameters between males and females. After 24 months of GHT, both males and females showed a significant increase in height (both P < 0.001), BMI (both P < 0.001), WC (P < 0.001 and P = 0.004, respectively), IGF-I (both P < 0.001), fasting glucose (P < 0.001 and P = 0.001, respectively), fasting insulin (both P < 0.001) and Homa-IR (both P < 0.001), with a concomitant significant decrease in insulin sensitivity index (ISI) (both P < 0.001) and oral disposition index (DIo) (P = 0.001 and P < 0.001, respectively). At 24 months of GHT, females showed significantly higher BMI (P = 0.027), lower ISI (P < 0.001) and DIo (P < 0.001), in concomitance with a significant greater change from baseline to 24 months of BMI (P = 0.013), WC (P < 0.001), ISI (P = 0.002) and DIo (P = 0.072), although the latter does not reach statistical significance.

CONCLUSIONS

Twenty-four months of GHT in prepubertal children leads to different metabolic outcomes according to gender, with a greater reduction in insulin sensitivity in females, regardless of auxological and hormonal parameters. Therefore, prepubertal GHD females should probably need a more proper monitoring in clinical practice.

Comparison between euglycemic hyperinsulinemic clamp and surrogate indices of insulin sensitivity in children with growth hormone deficiency

OBJECTIVE

Data about the impact of growth hormone treatment (GHT) on insulin sensitivity in children are quite controversial, due to the different surrogate indices that have been used.

DESIGN

We evaluated insulin sensitivity through the euglycemic hyperinsulinemic clamp, considered the gold standard technique, in 23 children affected by growth hormone deficiency (GHD) at baseline and after 12months of GHT and in 12 controls with short stature at baseline, and we compared the clamp-derived index (M-value) with the most commonly used surrogate index of insulin sensitivity, as ISI Matsuda, and with circulating plasma markers of insulin sensitivity, as adiponectin and resistin levels.

RESULTS

At baseline, no significant difference in all metabolic parameters between GHD children and control subjects was found. After 12months of GHT, GHD children showed a significant increase in fasting insulin (p<0.001) and resistin (p=0.028) and a decrease in ISI Matsuda (p<0.001) and M-value (p<0.001), without significant change in fasting glucose, HbA1c and adiponectin. In GHD children, M-value showed a significant but weak correlation with ISI Matsuda (rho 0.418, p=0.047) at baseline, while no correlation with other parameters was found. After 12months of GHT, M-value did not show any significant correlation with any other metabolic parameter analyzed.

CONCLUSIONS

This study highlights the limit of the evaluation of insulin sensitivity performed through surrogate indices or circulating markers, which may lead to controversial data and do not correlate with the gold standard technique to evaluate insulin sensitivity.

Correlation between adrenal function, growth hormone secretion, and insulin sensitivity in children with idiopathic growth hormone deficiency

PURPOSE

Patients with growth hormone deficiency (GHD) demonstrate an increased cortisol/cortisone ratio which could potentially explain the metabolic features of GHD, while GH treatment (GHT) could increase the cortisol metabolism.

METHODS

In 35 children (27 M, mean age 10.1 years) with idiopathic GHD at baseline and after 12 months of GHT and in 25 controls, in addition to metabolic parameters, we assessed adrenal function by morning serum cortisol, its peak, and its area under the curve (AUC_COR) during insulin tolerance test (ITT).

RESULTS

A cortisol peak <18 µg/dl was shown in 22 and 31% of GHD children at baseline and after GHT, respectively. At baseline, GHD children had lower fasting glucose (p < 0.001) and ISI-Matsuda (p = 0.042), with concomitant higher Homa-IR (p = 0.006) and morning cortisol (p = 0.012) than controls. Morning cortisol was negatively correlated with GH (p < 0.001), fasting glucose (p < 0.001) and ISI-Matsuda (p < 0.001) and positively with Homa-IR (p = 0.010). Both cortisol peak and AUC_COR were negatively correlated with GH (all p < 0.001) and ISI-Matsuda (p = 0.016 and p = 0.001, respectively). After 12 months of GHT, a significant increase in fasting glucose (p < 0.001), and Homa-IR (p = 0.011) was documented, with a concomitant decrease in morning cortisol (p = 0.002), AUC_COR (p = 0.038), total (p = 0.003) and LDL-cholesterol (p = 0.016). No significant correlations were found among cortisol levels and all parameters were investigated.

CONCLUSIONS

Cortisol levels correlate with GH secretion and with many metabolic parameters in GHD children, while the metabolic effects during GHT are mainly due to GHT per se and less to cortisol reduction.

Glucose Metabolism in Children With Growth Hormone Deficiency

BACKGROUND

The growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis has a fundamental impact on glucose metabolism. Therefore, both untreated GH deficiency (GHD) and GH treatment (GHT) may be associated with some metabolic alterations, although the abnormalities of glucose metabolism have been investigated by relatively few studies as main outcomes.

AIM

The present review summarizes the available data on glucose metabolism in children with GHD, providing an overview of the current state of the art in order to better clarify the real metabolic impact of GHD and GHT.

METHODS

Among all the existing studies, we evaluated all original studies that fulfilled our criteria for analysis reporting parameters of glucose metabolism as the primary or secondary objective.

RESULTS

The reported impact of GHD per se on glucose metabolism is quite homogeneous, with the majority of studies reporting no significant difference in metabolic parameters between GHD children and controls. Conversely, GHT proves to be more frequently associated with a subtle form of insulin resistance, while both fasting glucose and HbA1c levels remain almost always within the normal range.

CONCLUSION

The different methods to study glucose metabolism, the heterogeneity of the populations evaluated, the different doses of GH used together with the variable duration of follow-up may be responsible for discrepancy in the results. Long-term longitudinal studies having glucose homeostasis as their primary outcome are still needed in order better to clarify the real metabolic impact of GHD and GHT in children.

Association of genetic variants in RETN, NAMPT and ADIPOQ gene with glycemic, metabolic traits and diabetes risk in a Chinese population

Abnormal serum levels of adipokine have been established to be a strong predictor of developing several human diseases including type 2 diabetes mellitus (T2DM). Association studies have reported several genetic variants in genes coding adipokines with contributions to T2DM susceptibility as well as some glycemic and metabolic traits, of which the single nucleotide polymorphisms (SNPs) of RETN, NAMPT, and ADIPOQ gene were well documented. However, little is known about contributions of these SNPs to above phenotypes in Chinese. In the current study, with availably quantitative glycemic and metabolic data from a total of 185 T2DM patients and 191 healthy controls, we tested associations between four SNPs of RETN, NAMPT, ADIPOQ gene and 13 glycemic and metabolic traits. The results showed that the rs1862513 and rs34861192 of RETN gene were functional and negatively correlated with the levels of serum creatinine and cholesterol, respectively. The rs16861194 of ADIPOQ gene was positively correlated with the aspartate aminotransferase (AST) and AST/alanine aminotransferase level. Moreover, the rs34861192 and rs13237989 of NAMPT gene synergistically affected the levels of insulin and glycemic index. However, due to the limited sample size, only the rs16861194 exerted a significant increased risk on T2DM. These results underscore the contributions of SNPs in RETN, NAMPT, ADIPOQ gene to glycemic and metabolic traits as well as T2DM susceptibility in Chinese.

Growth Hormone's Effect on Adipose Tissue: Quality versus Quantity

Obesity is an excessive accumulation or expansion of adipose tissue (AT) due to an increase in either the size and/or number of its characteristic cell type, the adipocyte. As one of the most significant public health problems of our time, obesity and its associated metabolic complications have demanded that attention be given to finding effective therapeutic options aimed at reducing adiposity or the metabolic dysfunction associated with its accumulation. Growth hormone (GH) has therapeutic potential due to its potent lipolytic effect and resultant ability to reduce AT mass while preserving lean body mass. However, AT and its resident adipocytes are significantly more dynamic and elaborate than once thought and require one not to use the reduction in absolute mass as a readout of efficacy alone. Paradoxically, therapies that reduce GH action may ultimately prove to be healthier, in part because GH also possesses potent anti-insulin activities along with concerns that GH may promote the growth of certain cancers. This review will briefly summarize some of the newer complexities of AT relevant to GH action and describe the current understanding of how GH influences this tissue using data from both humans and mice. We will conclude by considering the therapeutic use of GH or GH antagonists in obesity, as well as important gaps in knowledge regarding GH and AT.

Impact of Growth Hormone on Regulation of Adipose Tissue

Increasing prevalence of obesity and obesity-related conditions worldwide has necessitated a more thorough understanding of adipose tissue (AT) and expanded the scope of research in this field. AT is now understood to be far more complex and dynamic than previously thought, which has also fueled research to reevaluate how hormones, such as growth hormone (GH), alter the tissue. In this review, we will introduce properties of AT important for understanding how GH alters the tissue, such as anatomical location of depots and adipokine output. We will provide an overview of GH structure and function and define several human conditions and cognate mouse lines with extremes in GH action that have helped shape our understanding of GH and AT. A detailed discussion of the GH/AT relationship will be included that addresses adipokine production, immune cell populations, lipid metabolism, senescence, differentiation, and fibrosis, as well as brown AT and beiging of white AT. A brief overview of how GH levels are altered in an obese state, and the efficacy of GH as a therapeutic option to manage obesity will be given. As we will reveal, the effects of GH on AT are numerous, dynamic and depot-dependent. © 2017 American Physiological Society. Compr Physiol 7:819-840, 2017.

Relationship between IGF-I Concentration and Metabolic Profile in Children with Growth Hormone Deficiency: The Influence of Children's Nutritional State as well as the Ghrelin, Leptin, Adiponectin, and Resistin Serum Concentrations

BACKGROUND

Some, however not all, children with growth hormone deficiency (GHD) reveal a tendency towards metabolic disorders. Insulin-like growth factor I (IGF-I) is the main mediator of GH anabolic effects.

OBJECTIVE

The aim of the study was to compare ghrelin, adiponectin, leptin, resistin, lipid, glucose, and insulin concentrations in GHD children, depending on the IGF-I bioavailability.

METHODS

The analysis comprised 26 children with GHD, aged 5.7-15.3 yrs. Fasting serum concentrations of IGF-I, IGFBP-3, ghrelin, leptin, adiponectin, resistin, lipids, glucose, and insulin were measured. The GHD children were divided into two subgroups: (1) with lower IGF-I/IGFBP-3 molar ratio and (2) with higher IGF-I/IGFBP-3 molar ratio. The control group consisted of 39 healthy children, aged 5.1-16.6 yrs, of normal height and body mass.

RESULTS

GHD children with lower IGF-I/IGFBP-3 molar ratio were found to have a significantly lower body mass and insulin and triglyceride concentrations, as well as significantly higher ghrelin and adiponectin concentrations than GHD children with higher IGF-I/IGFBP-3.

CONCLUSIONS

A better metabolic profile characterised GHD children with low IGF-I bioavailability. This phenomenon may be the result of high adiponectin and ghrelin concentrations in those children and their influence on adipose tissue, glucose uptake, and orexigenic axis.