Effects of Growth Hormone Treatment on Lipid Profiles

Growth hormone responses during arginine and clonidine stimulation test: Correlations with patients' auxological and metabolic parameters in a single centre study

BACKGROUND

Children with auxological parameters defining a 'short stature' is routinely subjected to various blood tests and, if necessary, to growth hormone stimulation test (GHST) for differentiating GH deficiency (GHD) and other causes of stunted growth.

AIM

This retrospective monocentric study aimed to evaluate any correlations between GH peaks during GHST in children assessed for short stature and their auxological/metabolic parameters, highlighting differences between GHD and idiopathic short stature.

PATIENTS AND METHODS

We reviewed the medical records of 74 children with short stature (height lower than the third percentile according to standardized growth curves for the Italian population) managed at the Pediatric Day Hospital of our Department of Life Sciences and Public Health in Università Cattolica Sacro Cuore, Rome, who performed at least two GHSTs, using arginine and clonidine as stimulants, for assessment of GH secretion. The results of a total number of 161 GHSTs, performed in 42 children diagnosed with GHD and in 32 children with other causes of short stature, were analyzed.

RESULTS

We found significantly lower serum levels of insulin growth factor-1 (IGF-1) and increased levels of thyroid-stimulating hormone (TSH) in children with GHD, without other metabolic differences in comparison to children with other causes of short stature. There was also a correlation between triglycerides and GH peak during arginine test, while fT4 and LDL concentrations correlated with GH peak during the third test, if performed. Pre-test BMI (rho -0.274, p = 0.01) and weight (rho -0.251, p = 0.03) have influenced GH peak during clonidine stimulation test. Metabolic and auxological parameters could influence GH peak during clonidine and arginine stimulation tests and must be taken into account when interpreting GHST results.

Effects of growth hormone on lipid metabolism and sexual development in pubertal obese male rats

To investigate the effects of growth hormone (GH) on pubertal obese male rats, a rat model of high-fat diet-induced obesity was established in juvenile male rats. The model rats were divided into the treatment group (GH) and the non-treatment group (physiological saline). After 4 weeks, we measured the levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), estrogen (E2), testosterone (T), and insulin-like growth factor (IGF-1). The morphological changes of the liver and testis were assessed, and the expression of aromatase was detected. The levels of ALT, AST, TC, TG, LDL-C, E2, and IGF-1 in the treatment group were significantly lower than in the non-treated model rats (P < 0.001). The levels of HDL-C and T of GH-treated rats were significantly higher than those of the non-treatment group (P < 0.001). Compared with non-treated model rats, GH-treated model rats showed reduced liver steatosis, improved morphological structure of the testicular seminiferous tubules, and an increased number of spermatogenic cells. The treatment group also showed lower expression of aromatase in the liver and testis compared with the non-treatment group. GH partially protected pubertal male rats from obesity-induced lipid metabolic disorder and sexual retardation.

Short-term efficacy and safety of a lower dose of polyethylene glycol recombinant human growth hormone in children with growth hormone deficiency: A randomized, dose-comparison study

Objective: Polyethylene glycol recombinant human growth hormone (PEG-rhGH, Jintrolong^®) is the first long-acting rhGH preparation that is approved to treat children with growth hormone deficiency (GHD) in China. Clinical experience with dose selections of PEG-rhGH is scarce. The present study compared the efficacy and safety of a lower dose to increase dosing regimens of PEG-rhGH treatment.

Methods: A multicenter, randomized, open-label, dose-comparison clinical study was conducted to compare the improvements in the height standard deviation score (Ht SDS), height velocity (HV), insulin-like growth factor-1 (IGF-1) SDS, and safety profiles of children with GHD who are treated with 0.2 mg/kg/week of PEG-rhGH dose or 0.14 mg/kg/week for 26 weeks.

Results: Ht SDS, HV, and IGF-1 SDS increased significantly after PEG-rhGH treatment in the two dose groups (p < 0.05). The improvements of Ht SDS, HV, and IGF-1 SDS were more significant in the high-dose group than in the low-dose group (p < 0.05). Ht SDS improvement in low-dose group was not non-inferiority to that in the high-dose group (p = 0.2987). The incidences of adverse events were comparable between the two groups.

Conclusion: The improvements of Ht SDS, HV, and IGF-1 SDS were more significant in the high-dose group than in the low-dose group (p < 0.05). PEG-rhGH at the dose of 0.14 mg/kg/week was effective and safe for children with GHD.

Clinical Trial Registration:clinicaltrials.gov, identifier NCT02908958.

Low-density lipoprotein cholesterol levels are associated with insulin-like growth factor-1 in short-stature children and adolescents: a cross-sectional study

BACKGROUND

Elevated low-density lipoprotein cholesterol (LDL-C) levels in childhood have recently been found to be the strongest predictive risk factor for coronary artery disease in adulthood. There is an increased level of LDL-C in children and adolescents with short stature. However, the underlying factors associated with increased LDL-C levels in children and adolescents with short stature are unknown. In addition, the insulin-like growth factor 1 (IGF-1) level in the short-stature population is usually below the normal reference range. The aim of this study was to investigate the relationship between IGF-1 standard deviation score (IGF-1 SDS) and LDL-C level in children and adolescents with short stature.

METHODS

A cross-sectional study was conducted in a single centre of China, 557 short-stature children and adolescents whose height SDS was lower than - 2 SD after adjustment for age and gender were included. The related clinical and laboratory examinations, including anthropometric parameters, lipid profiles, IGF-1 levels and the levels of other cofactors, were assessed in all participants.

RESULTS

The univariate analysis results showed a significant negative correlation between IGF-1 SDS and LDL-C levels (P = 0.006). Furthermore, a nonlinear relationship was observed between IGF-1 SDS and LDL-C by smooth curve fitting after adjusting for possible confounders. A multivariate piecewise linear regression model revealed a significant negative correlation between IGF-1 SDS and LDL-C when the IGF-1 level was greater than - 2 SDS (β - 0.07, 95% CI -0.12, - 0.02; P = 0.006). However, we did not observe a significant relationship between IGF-1 SDS and LDL-C when the IGF-1 level was lower than - 2 SDS (β 0.08, 95% CI -0.02, 0.17; P = 0.119).

CONCLUSION

This study demonstrated a nonlinear relationship between IGF-1 and LDL-C independent of other potential confounding factors, suggesting that circulating IGF-1 may contribute to the regulation of LDL-C levels, thus meriting further investigation.