Véronique Beauloye

Growth Hormone Research Society Workshop Summary: Consensus Guidelines for Recombinant Human Growth Hormone Therapy in Prader-Willi Syndrome

Context: Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events. Objective: The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS. Evidence: We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥ 6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries. Methodology: Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN). Conclusions: Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks.

Impairment of liver GH receptor signaling by fasting.

Fasting causes a state of GH resistance responsible for low circulating IGF-I levels. To investigate whether this resistance may result from alterations in the GH signaling pathway, we determined the effects of fasting on the GH transduction pathway in rat liver. Forty-eight-hour fasted or fed male rats were injected with recombinant rat GH via the portal vein. Liver was removed 0 and 15 min after injection. Although GH stimulated Janus kinase 2 (JAK2) phosphorylation in all animals, this was severely blunted in fasted animals. Similarly, the phosphorylation of the GH receptor, although observed in both fasted and fed rats after GH injection, was markedly reduced in fasted rats. A rapid signal transducer and activator of transcription 5 (STAT5) tyrosine phosphorylation was also induced in the liver of fed animals in response to GH. In contrast, in fasted rats only a slight phosphorylated STAT5 signal was observed. The inhibitory effect of fasting on these GH signaling molecules occurred without changes in their protein content. Furthermore, the impairment of the JAK-STAT pathway in fasted animals was associated with increased liver suppressor of cytokine signaling 3 mRNA levels. Although glucocorticoids, which are increased by fasting, may cause GH resistance, adrenalectomy failed to prevent alterations in the JAK-STAT pathway caused by fasting. In conclusion, the GH resistance induced by fasting is associated with impairment of the JAK-STAT signaling pathway. This might contribute to the decrease in liver IGF-I production observed in fasting.

Endocrine and metabolic disorders in young adult survivors of childhood acute lymphoblastic leukaemia (ALL) or non‐Hodgkin lymphoma (NHL)

Background  Treatments of acute lymphoblastic leukaemia (ALL) and non‐Hodgkin lymphoma (NHL), involving various combinations of chemotherapy (chemo), cranial irradiation (CI) and/or bone marrow transplantation after total body irradiation (BMT/TBI), are often successful but may have several long‐term harmful effects.

Effects of maternal protein malnutrition on fetal growth, plasma insulin-like growth factors, insulin-like growth factor binding proteins, and liver insulin-like growth factor gene expression in the rat.

ABSTRACT: We examined the effects of maternal dietary protein restriction on fetal growth and expression of IGF-I and -II, and IGF-binding proteins (IGFBP). We sought to dissociate the respective effects of maternal protein versus calorie restriction on growth indices and IGF synthesis by the neonates of protein-restricted dams. Pregnant Wistar rats (six to eight per group) fed a low (5%) protein diet throughout gestation had impaired body weight gain compared with controls fed a normal (20%) protein diet (by 45%, p < 0.001). Their serum and liver IGF-I concentrations and liver IGF-I mRNA concentrations were also reduced by 60, 80, and 50%, respectively. Serum IGFBP-3 was reduced by 60% in protein-restricted dams within 1 to 2 h after delivery (p < 0.001 versus controls), although IGFBP-1, -2, and -4 were not significantly affected by the dietary protein intake. In pups of protein-restricted dams, the mean body and liver weight at birth was 15–20% less than that observed in the progeny from normal protein-fed dams (p < 0.01). Their plasma and liver IGF-I concentrations were 30 and 60% lower, respectively, whereas liver IGF-I mRNA abundance was reduced by 50% (p < 0.01). In contrast, neonatal plasma IGF-II and liver IGF-II mRNA concentrations were not significantly affected by the maternal protein malnutrition. Also, the plasma levels of IGFBP were not altered in the growth-retarded pups. Maternal protein restriction did not affect fetal and placental growth, plasma and liver IGF-I levels, and liver IGF-I mRNA abundance in 20-d-old fetuses. We conclude that intrauterine growth retardation caused by maternal protein malnutrition is associated with reduced neonatal expression of the IGF-I gene without obvious changes in IGF-II gene expression and plasma IGFBP concentrations. These results support the emerging evidence that IGF-I may play a role in the regulation of fetal growth and development.

Long-term effects of gestational protein malnutrition on postnatal growth, insulin-like growth factor (IGF)-I, and IGF-binding proteins in rat progeny.

We examined the long-term effects of dietary protein restriction during rat pregnancy on serum IGF-I, serum IGF binding proteins, and liver IGF-I gene expression during postnatal development. Pregnant Wistar rats were fedad libitum throughout gestation a normal (20% casein diet; P20 controls) or a low (5% casein; P5) protein diet. At birth, the pups from both P20 and P5 dams were cross-fostered to well nourished lactating dams, and litters (n = 5/dietary group) were reduced in size to 6 pups. After weaning (d 22), the pups were fed the control diet ad libitum. The pups were killed at 8, 22, and 63 d of age. Gestational protein restriction caused significant growth retardation and mortality in newborn pups. Despite food rehabilitation during the suckling period (d 0-22), body weight, tail length, and the weight of liver, heart, kidney, and brain in the P5 pups remained significantly reduced at 8 and 22 d (-17 to -35%) compared with control pups. At the same time, serum and liver IGF-I concentrations in the P5 pups (on d 8: 100 ± 9 ng/mL and 11 ± 1 ng/g, respectively; on d 22: 340 ± 20 ng/mL and 42 ± 3 ng/g) were lower than in age-matched controls (on d 8: 170 ± 12 ng/mL and 26 ± 2 ng/g; on d 22: 470 ± 30 ng/mL and 73 ± 5 ng/g), although liver IGF-I mRNA abundance was not affected. After long-term food rehabilitation (d 63), tail length and organ weight recovered, and serum and liver IGF-I concentrations were normalized. However, although the P5 rats had resumed a normal growth rate, their body weight remained lower than in the controls. There were no differences in serum IGF binding proteins 1-4, insulin, and GH concentrations between the groups at any age studied. These results suggest that reduction in serum IGF-I may contribute to the reduced somatic and organ growth observed in rats after gestational protein malnutrition, and further support a role for IGF-I in the control of catch-up growth.

Long-Term Effects on Bone Mineral Density of Different Therapeutic Schemes for Acute Lymphoblastic Leukemia or Non-Hodgkin Lymphoma during Childhood

Background: Little is known regarding long-term bone deficit in relationship with the modalities of cancer therapy among survivors of childhood malignancy. Methods: Bone mineral density (BMD) was evaluated at lumbar spine (LS), total hip and femoral neck in 89 patients (44 men) more than 5 years after remission of childhood acute lymphoblastic leukemia (ALL) or non-Hodgkin lymphoma (NHL). The patients had received chemotherapy (group I; n = 41), chemotherapy and cranial irradiation (group II; n = 32), or bone marrow transplantation (BMT) with total body irradiation (TBI) (group III; n = 16). All patients had received methylprednisolone and 47 additional dexamethasone treatment. Results: A reduced BMD at any site was observed in 44 of the 89 patients, more frequently in men (66%) than women (33%) (p < 0.001). In comparison with group I, mean BMD was significantly lower at all sites in group II and at the total hip and femoral neck in group III. A multivariate analysis showed independent significant influences of male gender at LS (p < 0.001) and of type of treatment and dexamethasone at the hip (p < 0.05). Conclusions: A low bone mass is frequently observed in adult survivors of childhood ALL and NHL, and is associated with male gender at the LS and with dexamethasone treatment, cranial irradiation and BMT/TBI at the hip.

GHRH excess and blockade in X-LAG syndrome

X-linked acrogigantism (X-LAG) syndrome is a newly described form of inheritable pituitary gigantism that begins in early childhood and is usually associated with markedly elevated GH and prolactin secretion by mixed pituitary adenomas/hyperplasia. Microduplications on chromosome Xq26.3 including the GPR101 gene cause X-LAG syndrome. In individual cases random GHRH levels have been elevated. We performed a series of hormonal profiles in a young female sporadic X-LAG syndrome patient and subsequently undertook in vitro studies of primary pituitary tumor culture following neurosurgical resection. The patient demonstrated consistently elevated circulating GHRH levels throughout preoperative testing, which was accompanied by marked GH and prolactin hypersecretion; GH demonstrated a paradoxical increase following TRH administration. In vitro, the pituitary cells showed baseline GH and prolactin release that was further stimulated by GHRH administration. Co-incubation with GHRH and the GHRH receptor antagonist, acetyl-(d-Arg(2))-GHRH (1-29) amide, blocked the GHRH-induced GH stimulation; the GHRH receptor antagonist alone significantly reduced GH release. Pasireotide, but not octreotide, inhibited GH secretion. A ghrelin receptor agonist and an inverse agonist led to modest, statistically significant increases and decreases in GH secretion, respectively. GHRH hypersecretion can accompany the pituitary abnormalities seen in X-LAG syndrome. These data suggest that the pathology of X-LAG syndrome may include hypothalamic dysregulation of GHRH secretion, which is in keeping with localization of GPR101 in the hypothalamus. Therapeutic blockade of GHRH secretion could represent a way to target the marked hormonal hypersecretion and overgrowth that characterizes X-LAG syndrome.

Characteristics and determinants of partial remission in children with type 1 diabetes using the insulin-dose-adjusted A1C definition.

To evaluate the characteristics and determinants of partial remission (PR) in Belgian children with type 1 diabetes (T1D), we analyzed records of 242 children from our center. Clinical and biological features were collected at diagnosis and during follow-up. PR was defined using the insulin-dose-adjusted A1C definition. PR occurred in 56.2% of patients and lasted 9.2 months (0.5 to 56.6). 25.6% of patients entered T1D with DKA, which correlated with lower PR incidence (17.6% versus 82.3% when no DKA). In our population, lower A1C levels at diagnosis were associated with higher PR incidence and in young children (0–4 years) initial A1C levels negatively correlated with longer PR. Early A1C levels were predictive of PR duration since 34% of patients had long PRs (>1 year) when A1C levels were ≤6% after 3 months whereas incidence of long PR decreased with higher A1Cs. C-peptide levels were higher in patients entering PR and remained higher until 3 years after diagnosis. Initial antibody titers did not influence PR except for anti-IA2 titers that correlated with A1C levels after 2 years. Presence of 2 versus 1 anti-islet antibodies correlated with shorter PR. PR duration did not influence occurrence of severe hypoglycemia or diabetes-related complications but was associated with lower A1C levels after 18 months. We show that, at diagnosis of T1D, parameters associated with β-cell mass reserve (A1C, C-peptide, and DKA) correlate with the occurrence of PR, which affects post-PR A1C levels. Further research is needed to determine the long-term significance of PR.

Regulation of Insulin-like Growth Factor-I by Nutrition

Nutrition is one of the principal regulators of circulating IGF-I. Many mechanisms are involved in the nutritional regulation of IGF-I. Both energy and protein are critical to the regulation of serum IGF-I concentrations. After fasting, adequate energy and protein are necessary for restoration of serum IGF-I, but energy may be somewhat more important than protein. While a low intake of protein is able to increase IGF-I in the presence of adequate energy, there is a threshold requirement of energy below which optimal protein intake fails to raise IGF-I after fasting. The decline of serum IGF-I during dietary restriction is independent of diet-induced alterations in pituitary GH secretion. In severe dietary restriction (fasting), a marked decrease in the number of liver somatogenic receptors suggests that a GH receptor defect is involved in the decline of serum IGF-I. In protein restriction, the decline of serum IGF-I results from a postreceptor defect in GH action at the hepatic level. Nutritional deprivation decreases hepatic IGF-I production by diminishing IGF-I gene expression. Decline in IGF-I gene expression results from both transcriptional and post-transcription mechanisms. Diet restriction also increases the clearance and degradation of serum IGF-I through changes in the levels of circulating IGFBPs. The molecular mechanisms leading to the decline of IGF-I in catabolic stress seem to be similar to those operational in food deprivation. Nutrients may also control the biological action of IGF-I, either directly or indirectly, through changes in IGFBPs.

Characterization of insulin resistance in young adult survivors of childhood acute lymphoblastic leukaemia and non-Hodgkin lymphoma

An increased prevalence of metabolic disorders and cardiovascular (CV) disease has been reported in childhood acute lymphoblastic leukaemia (ALL)/non‐Hodgkin lymphoma (NHL) cancer survivors.