Two years in growth hormone 2017-18

Growth hormone treatment in aged patients with comorbidities: A systematic review

OBJECTIVE

Hormonal substitution with growth hormone in aged patients remains a debated research topic and is rarely initiated in clinical practice. This reluctance may originate from concerns about adverse effects and the uncritical use as an anti-aging agent. Nevertheless, beneficial effects for selected patients suffering from certain acute and chronic illnesses could justify its use at an advanced age. This systematic review analyzes randomized controlled studies of GH interventions in older patients with different comorbidities to assess both, beneficial and harmful effects.

DESIGN

A systematic search strategy was implemented to identify relevant studies from PubMed, MEDLINE, and The Cochrane Library.

INCLUSION CRITERIA

participants aged over 65 years, randomized controlled trials involving human growth hormone (GH) and presence of at least one additional comorbidity independent of a flawed somatotropic axis.

RESULTS

The eight eligible studies encompassed various comorbidities including osteoporosis, frailty, chronic heart failure, hip fracture, amyotrophic lateral sclerosis and hemodialysis. Outcomes varied, including changes in body composition, physical performance, strength, bone mineral density, cardiovascular parameters, quality of life and housing situation. Study protocols differed greatly in GH application frequency (daily, 2nd day or 3×/week), doses (0.41 mg-2.6 mg; mean 1.3 mg per 60 kg patient) and duration (1-12 months; mean 7 months). Mild dose-related side effects were reported, alongside noticeable positive impacts particularly on body composition, functionality, and quality of life.

CONCLUSION

Despite limited evidence, GH treatment might offer diverse benefits with few adverse effects. Further research with IGF-I dependent indication and clear outcomes, incorporating IGF-I dependent GH titration in older adults is warranted.

Diagnosing Growth Hormone Deficiency: Can a Combined Arginine and Clonidine Stimulation Test Replace 2 Separate Tests?

OBJECTIVE

Given the large number of false-positive growth hormone deficiency (GHD) diagnoses from a single growth hormone (GH) stimulation test in children, 2 different pharmacologic tests, performed on separate days or sequentially, are required. This study aimed to assess the reliability and safety of a combined arginine-clonidine stimulation test (CACST).

METHODS

This was a retrospective, single-center, observational study. During 2017-2019, 515 children aged >8 years underwent GH stimulation tests (CACST: n = 362 or clonidine stimulation test [CST]: n = 153). The main outcome measures used to compare the tests were GH response (sufficiency/deficiency) and amplitude and timing of peak GH and safety parameters.

RESULTS

Population characteristics were as follows: median age of 12.2 years (interquartile range [IQR]: 10.7, 13.4), 331 boys (64%), and 282 prepubertal children (54.8%). The GHD rate was comparable with 12.7% for CACST and 14.4% for CST followed by a confirmatory test (glucagon or arginine) (P = .609). Peak GH was higher and occurred later in response to CACST compared with CST (14.6 ng/mL [IQR: 10.6, 19.4] vs 11.4 ng/mL [IQR: 7.0, 15.8], respectively, P < .001; 90 minutes [IQR: 60, 90] vs 60 minutes [IQR: 60, 90], respectively, P < .001). No serious adverse events occurred following CACST.

CONCLUSION

Our findings demonstrate the reliability and safety of CACST in detecting GHD in late childhood and adolescence, suggesting that it may replace separate or sequential GH stimulation tests. By diminishing the need for the second GH stimulation test, CACST saves time, is more cost-effective, and reduces discomfort for children, caregivers, and medical staff.

Endoplasmic reticulum stress induces growth retardation by inhibiting growth hormone IGF-I axis

OBJECTIVE

Insulin-like growth factor 1 (IGFI) is one of several growth factors which is induced by growth hormone (GH), which activates the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) pathway, and plays crucial roles in normal human growth, metabolism, and systemic energy homeostasis. However, little is known about the negative regulation of IGF-I production under different physiological or pathological conditions. Herein, we explore whether activation of endoplasmic reticulum (ER) stress regulates IGF-I production and normal body growth.

MATERIALS AND METHODS

C57BL/6 J mice were challenged with tunicamycin (Tm) to induce ER stress activation. 24 h after stimulation, hepatic mRNA expression was analyzed by RNA-Seq and validated by qPCR. Enzyme-linked immunosorbent assay (ELISA) was performed 24 h after Tm stimulation. Body growth was determined 16 days after Tm stimulation. Animals were then sacrificed and liver tissues were collected for further analysis.

RESULTS

Mice challenged with Tm displayed a retardation of growth. Molecularly, we found that ER stress inhibited phosphorylation of STAT5. IGF-I transcription and circulating IGF-I were also dramatically decreased under ER stress activation. Moreover, our results demonstrate that IGF-I administration ameliorates Tm-induced growth retardation.

CONCLUSIONS

ER stress induces growth retardation. ER stress inhibits hepatic GH-JAK2 signaling activation and its downstream target gene expression. These results warrant further research to explore the crosstalk between ER stress and growth hormone signaling in improving body growth.