Increased neutrophil insulin-like growth factor-I (IGF-I) receptor expression and IGF-I-induced functional capacity in patients with untreated Laron syndrome

• Published in: European journal of endocrinology Vol. 136; no. 1; pp. 92 - 95
• Main Authors: BJERKNES, R, VESTERHUS, P, AARSKOG, D
• Format: Journal Article
• Language: English
• Published: Colchester Portland Press 01.01.1997
• Subjects: Biological and medical sciences; CASE REPORTS; Child; Endocrinopathies; Female; Growth Disorders - drug therapy; Growth Disorders - physiopathology; Humans; Hypothalamus. Hypophysis. Epiphysis (diseases); Immunohistochemistry; Insulin-Like Growth Factor I - deficiency; Insulin-Like Growth Factor I - therapeutic use; Male; Medical sciences; Neutrophils - drug effects; Neutrophils - metabolism; Neutrophils - physiology; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Phagocytosis - drug effects; Receptor, IGF Type 1 - drug effects; Receptor, IGF Type 1 - metabolism; Respiratory Burst - drug effects; Syndrome; Time Factors; Human; Laron dwarfism; Pathogenesis; Neutrophil; Gene expression; Insulin like growth factor 1; Cell surface; Functional capacity; Biological receptor
• ISSN: 0804-4643; 1479-683X
• DOI: 10.1530/eje.0.1360092

Abstract Insulin-like growth factor-I (IGF-I) is a growth hormone-dependent peptide with growth and immunoregulatory properties, and in Laron syndrome growth hormone insensitivity induces impaired production of IGF-I. In the present study we have determined the neutrophil expression of IGF-I receptors (IGF-I-Rs), as well as the IGF-I-induced priming of neutrophil functional capacity, in two children with Laron syndrome treated with recombinant human IGF-I, and in age-matched controls. Before treatment, the patient neutrophil expression of IGF-I-Rs was significantly increased. However, with replacement therapy the neutrophil IGF-I-R expression was downregulated to levels similar to those of the controls within one month. In the patients, the phagocytic capacity and oxidative burst of unprimed neutrophils were normal and similar to controls before the start of treatment. Moreover, IGF-I efficiently primed both patient and control neutrophils to increase their phagocytic capacity and oxidative burst in vitro. However, before therapy, the priming response to IGF-I was significantly stronger in the neutrophils in the patients than in the controls. The present data support earlier studies by us and others demonstrating that IGF-I is a potent regulator of mature neutrophil function, but also suggest that these leukocytes may function normally in the presence of very low levels of IGF-I in vivo. European Journal of Endocrinology 136 92–95