The Efficacy of GnRHa Alone or in Combination with rhGH for the Treatment of Chinese Children with Central Precocious Puberty

Gonadotropin-releasing hormone analogue and recombinant human growth hormone treatment for idiopathic central precocious puberty in girls

PURPOSE

To investigate the effectiveness and safety of gonadotropin-releasing hormone analogue (GnRHa) in combination with recombinant human growth hormone (rhGH) in girls with central precocious puberty (CPP).

METHODS

Clinical data of 80 girls diagnosed with idiopathic central precocious puberty (ICPP) between January 2017 and June 2021 were retrospectively analyzed. Treatment strategy involved GnRHa alone (group A: n=34) and GnRHa+rhGH (group B: n=46). Children's heights (Ht), weights (Wt) and sex hormone levels were measured every 3 months after treatment and bone age (BA) every six months. Heights, growth velocity (GV), predicted adult height (PAH), weights, body mass index (BMI), sex hormone levels and bone age were compared between the two groups.

RESULTS

Children in group B showed greater height gain at the 12th, 24th and 30th months after treatment (p<0.05) than those in group A, had faster growth rates in the first and second year following treatment (p<0.05) and better PAH (p<0.05). No statistical differences in weight or BMI were found between the two groups before treatment or at any time after treatment (p>0.05). Levels of LH and FSH were lower in both groups after treatment with no statistical differences between groups (p>0.05). The gap between bone age and chronological age gradually decreased in both groups and no abnormal progression of bone age or other adverse side effects occurred.

CONCLUSIONS

The combination of GnRHa with rhGH produced better height gains than GnRHa alone for patients with CPP. The gonadal axis was suppressed and progression of bone age delayed with good safety and efficacy.

Buserelin Inhibits the Immunosuppressive Activity of Regulatory T Cells through the Protein Kinase A Signaling in a Central Precocious Puberty Model

Background: Gonadotropin-releasing hormone analogs (GnRHas) are used for treating central precocious puberty (CPP). However, their roles in the regulation of immune cells especially regulatory T cells (Tregs) remains elusive. Therefore, we characterized buserelin-induced phenotypical and functional changes of Tregs.Methods: A rat CPP model was established followed by administration of buserelin acetate. Flow cytometry was used to evaluate the expression of functional molecules in splenic Tregs. The suppressive activity of Tregs was determined by the suppression assay. GnRHR expression in Tregs was assessed by flow cytometry analysis and Immunoblotting. Normal Tregs were then stimulated and treated with buserelin acetate in vitro. After that, Foxp3 expression, Treg proliferation, and cytokine production were analyzed by flow cytometry. Intracellular signaling was evaluated by Immunoblotting, and Treg function was determined by the suppression assay.Results: After in vivo buserelin treatment, the frequency of splenic Tregs was decreased, with the reduction in the expression of Foxp3, IL-10, and TGF-β. The suppressive activity of Tregs was weakened. Buserelin down-regulated Foxp3 expression while promoting the expression of RORγt and IL-17 in Tregs through activating the protein kinase A (PKA) pathway in vitro. The PKA inhibitor H-89 abolished the effect of buserelin and enhanced Treg function.Conclusion: Buserelin impaired the immunosuppressive activity of Tregs through the PKA signal pathway. Buserelin-induced activation of PKA signaling down-regulated Foxp3 expression while promoting RORγt expression in Tregs, and subsequently weakened Treg function. Our study indicates the necessity of monitoring Treg activity in CPP patients to avoid potential autoimmunity or inflammation.

Effects of Recombinant Human Growth Hormone on the Onset of Puberty, Leydig Cell Differentiation, Spermatogenesis and Hypothalamic KISS1 Expression in Immature Male Rats

Purpose

Recombinant human growth hormone (rhGH) has been used to treat short stature and rhGH-related syndromes. However, there are concerns that rhGH-treatment may cause precocious puberty. We investigated the effects of rhGH-treatment on the puberty onset, sexual maturation, androgen production, and hypothalamic gene expression in prepubertal male rats.

Materials and Methods

Sprague-Dawley male rats were injected subcutaneously daily with 1 or 2 IU/kg/d rhGH or 0.1 mL saline from postnatal day (PND) 21 to 30. At PND 31 bodyweight, reproductive organs weight, preputial separation, testis histology, circulating testosterone, and expression of testicular steroidogenic pathway genes and hypothalamic Kiss1 were examined.

Results

By day 4 of injection bodyweights of rhGH groups were significantly higher than those of controls. rhGH 2 IU group showed earlier preputial separation compared to the control group. At PND 31, the weights of testes, epididymides, seminal vesicles, prostates, and preputial glands of the 2 IU-rhGH group were significantly higher than control group. Serum testosterone levels of the 2 IU-rhGH group were significantly higher than control group. Testicular steroidogenic pathway gene Hsd17b3 and Nr5a1 mRNA and cell counts and areas of Leydig cells in rhGH groups were significantly higher than control group, suggesting functional differentiation of Leydig cells. Hypothalamic Kiss1 mRNA levels of the 1 IU-rhGH group were significantly lower than control group, suggesting negative feedback of Kiss1 by elevated testosterone.

Conclusions

Prepubertal rhGH-treatment in male rats may induce early onset of puberty, sexual maturation, elevation of testosterone, and spermatogenesis, and accompanies downregulation of hypothalamic KISS1.

Should Skeletal Maturation Be Manipulated for Extra Height Gain?

Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI). These agents have been investigated in children with growth disorders (off-label), either alone or in combination with recombinant human growth hormone (rhGH). GnRHa is effective in attaining a normal adult height (AH) in the treatment of children with central precocious puberty, but its effect in short children with normal timing of puberty is equivocal. If rhGH-treated children with growth hormone deficiency or those who were born small-for-gestational age are still short at pubertal onset, co-treatment with a GnRHa for 2-3 years increases AH. A similar effect was seen by adding rhGH to GnRHa treatment of children with central precocious puberty with a poor AH prediction and by adding rhGH plus GnRHa to children with congenital adrenal hyperplasia with a poor predicted adult height on conventional treatment with gluco- and mineralocorticoids. In girls with idiopathic short stature and relatively early puberty, rhGH plus GnRHa increases AH. Administration of letrozole to boys with constitutional delay of growth puberty may increase AH, and rhGH plus anastrozole may increase AH in boys with growth hormone deficiency or idiopathic short stature, but the lack of data on attained AH and potential selective loss-of-follow-up in several studies precludes firm conclusions. GnRHas appear to have a good overall safety profile, while for aromatase inhibitors conflicting data have been reported.