GH Resistance Is a Component of Idiopathic Short Stature: Implications for rhGH Therapy

Ghrelin alleviated TiO2 NPs-induced inhibition of endochondral osteogenesis and promoted longitudinal growth of long bones in juvenile rats via Wnt/β-catenin signaling pathway

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in children's daily necessities and foods, and their health hazards to children have attracted particular attention. Childhood is a critical time for accelerated bone growth and development. Current studies revealed that TiO2 NPs exposure causes bone damage in juvenile rats; however, the underlying mechanism is unknown. Ghrelin is a polypeptide hormone that is considered to be a candidate factor for regulating bone growth and development. In this research, 3-week-old juvenile male rats were administered 0, 100 or 200 mg/kg TiO2 NPs and 50 μg/kg ghrelin for 4 weeks to explore the underlying mechanism of TiO2 NPs-induced bone damage, and the protective effect of ghrelin. Our results revealed that TiO2 NPs resulted in decreased synthesis of bone growth-related hormones, disturbed bone metabolism, and destruction of bone structure. Further mechanism studies showed that TiO2 NPs inhibited Wnt/β-catenin pathway, reduced collagen synthesis, inhibited chondrocyte proliferation and differentiation, promoted chondrocyte apoptosis, and inhibited endochondral osteogenesis, ultimately leading to long bone longitudinal growth retardation and osteoporosis. Ghrelin alleviated the negative effects of TiO2 NPs-induced bone growth in juvenile rats by upregulating the Wnt/β-catenin signaling pathway. This study provided a reference for the clinical treatment of growth retardation and idiopathic short stature in juvenile children caused by environmental pollutants.

Liver impact of growth hormone (GH) intermittent treatment during the growth period in mice

Liver impact of prolonged GH-treatment given to non-GH-deficient growing mice between the third and eighth week of life was evaluated in both sexes. Tissues were collected 6 h after last dose or four weeks later. Somatometric, biochemical, histological, immunohistochemical, RT-qPCR and immunoblotting determinations were performed. Five-week GH intermittent administration induced body weight gain and body and bone length increase, augmented organ weight, higher hepatocellular size and proliferation, and increased liver IGF1 gene expression. Phosphorylation of signaling mediators and expression of GH-induced proliferation-related genes was decreased in GH-treated mice liver 6h after last injection, reflecting active sensitization/desensitization cycles. In females, GH elicited EGFR expression, associated to higher EGF-induced STAT3/5 phosphorylation. Four weeks after treatment, increased organ weight concomitant to body weight gain was still observed, whereas hepatocyte enlargement reverted. However, basal signaling for critical mediators was lower in GH-treated animals and in male controls compared to female ones, suggesting signaling declination.

Association between the uric acid to high density lipoprotein cholesterol ratio and alanine transaminase in Chinese short stature children and adolescents: A cross-sectional study

Objective

Uric acid to high-density lipoprotein cholesterol ratio (UHR), the ratio of uric acid to high-density lipoprotein cholesterol, is a newly proposed marker of metabolic abnormalities. There are few previous studies directly investigating the relationship between UHR and alanine aminotransferase (ALT), especially in short stature populations, however, short stature children and adolescents are more likely to have metabolic disorders. This research aimed to investigate the relationship between the UHR and ALT in children and adolescents with short stature.

Methods

In this cross-sectional analysis, the clinical data of 1,510 children with height below -2 SD who were evaluated at the Department of Endocrinology, Affiliated Hospital of Jining Medical University from 1 March 2013 to 31 December 2021, were selected. Anthropometric and biochemical indicators were measured. The relationship between UHR and ALT was analysed.

Results

The univariate analysis results showed that UHR was positively associated with ALT (β = 0.43, P < 0.0001). Furthermore, after adjusting for possible confounding factors, a non-linear relationship was detected between UHR and ALT through smooth curve fitting, and the inflection point of UHR was 10.93% after multivariate piecewise linear regression analysis. ALT increased with UHR elevation when the UHR was greater than 10.93% (β = 0.69, 95% CI 0.39, 0.98; P < 0.0001). However, we did not observe a significant relationship when the UHR was less than 10.93% (P = 0.9229).

Conclusion

Our study demonstrated that in Chinese children and adolescents with short stature, UHR may be associated with the regulation of ALT levels, and this relationship merits further investigation.

Children With Short Stature Display Reduced ACE2 Expression in Peripheral Blood Mononuclear Cells

BACKGROUND

The cause of short stature remains often unknown. The renin-angiotensin system contributes to growth regulation. Several groups reported that angiotensin-converting enzyme 2 (ACE2)-knockout mice weighed less than controls. Our case-control study aimed to investigate if children with short stature had reduced ACE2 expression as compared to controls, and its significance.

MATERIALS AND METHODS

children aged between 2 and 14 years were consecutively recruited in a University Hospital pediatric tertiary care center. Cases were children with short stature defined as height SD ≤ -2 diagnosed with growth hormone deficiency (GHD) or idiopathic short stature (ISS), before any treatment. Exclusion criteria were: acute diseases, kidney disease, endocrine or autoimmune disorders, precocious puberty, genetic syndromes, SGA history. ACE and ACE2 expression were measured in peripheral blood mononuclear cells, angiotensins were measured by ELISA.

RESULTS

Children with short stature displayed significantly lower ACE2 expression, being 0.40 fold induction (0.01-2.27) as compared to controls, and higher ACE/ACE2, with no differences between GHD and ISS. ACE2 expression was significantly and inversely associated with the risk of short stature, OR 0.26 (0.07-0.82), and it had a moderate accuracy to predict it, with an AUC of 0.73 (0.61-0.84). The cutoff of 0.45 fold induction of ACE2 expression was the value best predicting short stature, identifying correctly 70% of the children.

CONCLUSIONS

Our study confirms the association between the reduction of ACE2 expression and growth retardation. Further studies are needed to determine its diagnostic implications.