Ralph Decker

Metabolic outcome of GH treatment in prepubertal short children with and without classical GH deficiency

Context  Few studies have evaluated the metabolic outcomes of growth hormone (GH) treatment in idiopathic short stature (ISS). Moreover, children with ISS appear to need higher GH doses than children with GH deficiency (GHD) to achieve the same amount of growth and may therefore be at increased risk of adverse events during treatment. The individualized approach using prediction models for estimation of GH responsiveness, on the other hand, has the advantage of narrowing the range of growth response, avoiding too low or high GH doses.

Different thresholds of tissue-specific dose-responses to growth hormone in short prepubertal children

BackgroundIn addition to stimulating linear growth in children, growth hormone (GH) influences metabolism and body composition. These effects should be considered when individualizing GH treatment as dose-dependent changes in metabolic markers have been reported. Hypothesis: There are different dose-dependent thresholds for metabolic effects in response to GH treatment.MethodA randomized, prospective, multicentre trial TRN 98-0198-003 was performed for a 2-year catch-up growth period, with two treatment regimens (a) individualized GH dose including six different dose groups ranging from 17–100 μg/kg/day (n=87) and (b) fixed GH dose of 43 μg/kg/day (n=41). The individualized GH dose group was used for finding dose–response effects, where the effective GH dose (ED 50%) required to achieve 50% Δ effect was calculated with piecewise linear regressions.ResultsDifferent thresholds for the GH dose were found for the metabolic effects. The GH dose to achieve half of a given effect (ED 50%, with 90% confidence interval) was calculated as 33(±24.4) μg/kg/day for Δ left ventricular diastolic diameter (cm), 39(±24.5) μg/kg/day for Δ alkaline phosphatase (μkat/L), 47(±43.5) μg/kg/day for Δ lean soft tissue (SDS), 48(±35.7) μg/kg/day for Δ insulin (mU/L), 51(±47.6) μg/kg/day for Δ height (SDS), and 57(±52.7) μg/kg/day for Δ insulin-like growth factor I (IGF-I) SDS. Even though lipolysis was seen in all subjects, there was no dose–response effect for Δ fat mass (SDS) or Δ leptin ng/ml in the dose range studied. None of the metabolic effects presented here were related to the dose selection procedure in the trial.ConclusionsDose-dependent thresholds were observed for different GH effects, with cardiac tissue being the most responsive and level of IGF-I the least responsive. The level of insulin was more responsive than that of IGF-I, with the threshold effect for height in the interval between.

Protein profiling identified dissociations between growth hormone-mediated longitudinal growth and bone mineralization in short prepubertal children

Growth hormone (GH) promotes longitudinal growth and bone mineralization. In this study, a proteomic approach was used to analyze the association between serum protein expression pattern and height-adjusted bone mineralization in short prepubertal children receiving GH treatment. Patterns of protein expression were compared with those associated with longitudinal bone growth. Specific protein expression patterns associated with changes in height-adjusted bone mineralization in response to GH treatment were identified. Out of the 37 peaks found in significant regression models, 27 were uniquely present in models correlated with changes in bone mineralization and 7 peaks were uniquely present in models correlated with changes in height. The peaks identified corresponded to apolipoproteins, transthyretin, serum amyloid A4 and hemoglobin beta. We conclude that a proteomic approach could be used to identify specific protein expression patterns associated with bone mineralization in response to GH treatment and that height-adjusted bone mineralization and longitudinal bone growth are regulated partly by the same and partly by different mechanisms. Protein isoforms with different post-translational modifications might be of importance in the regulation of these processes. However, further validation is needed to assess the clinical significance of the results.

ORIGINAL ARTICLE: Metabolic outcome of GH treatment in prepubertal short children with and without classical GH deficiency

Context  Few studies have evaluated the metabolic outcomes of growth hormone (GH) treatment in idiopathic short stature (ISS). Moreover, children with ISS appear to need higher GH doses than children with GH deficiency (GHD) to achieve the same amount of growth and may therefore be at increased risk of adverse events during treatment. The individualized approach using prediction models for estimation of GH responsiveness, on the other hand, has the advantage of narrowing the range of growth response, avoiding too low or high GH doses.

Protein markers predict body composition during growth hormone treatment in short prepubertal children

A high‐throughput pharmaco‐proteomic approach has previously been successfully used to identify lipoprotein biomarkers related to changes in longitudinal growth and bone mass in response to growth hormone (GH) treatment.

Decreased GH dose after the catch-up growth period maintains metabolic outcome in short prepubertal children with and without classic GH deficiency

Few studies have evaluated metabolic outcomes following growth hormone (GH) treatment in short prepubertal children during different periods of growth. Previously, we found that individualized GH dosing in the catch‐up period reduced the variation in fasting insulin levels by 34% compared with those receiving a standard GH dose. We hypothesized that the GH dose required to maintain beneficial metabolic effects is lower during the prepubertal growth phase after an earlier catch‐up growth period.

GH dose reduction maintains normal prepubertal height velocity after initial catch up growth in short children.

Context GH responsiveness guides GH dosing during the catch-up growth (CUG) period; however, little is known regarding GH dosing during the prepubertal maintenance treatment period. Objective To evaluate whether SD score (SDS) channel parallel growth with normal height velocity can be maintained after CUG by reducing the GH dose by 50% in children receiving doses individualized according to estimated GH responsiveness during the catch-up period. Design and Settings Prepubertal children (n = 98; 72 boys) receiving GH during CUG (GH deficient, n = 33; non-GH deficient, n = 65), were randomized after 2 to 3 years to either a 50% reduced individualized dose (GHRID; n = 27; 20 boys) or unchanged individualized dose (GHUID; n = 38; 27 boys). Another 33 children (25 boys) continued a standard weight-based dose [43 µg/kg/d (GHFIX)]. Main Outcome Measures The primary endpoint was the proportion of children with ΔheightSDS within ±0.3 at 1 year after GH dose reduction compared with two control groups: GHUID and GHFIX. The hypothesis was that heightSDS could be maintained within ±0.3 with a reduced individualized GH dose. Results For the intention-to-treat population at 1 year, 85% of the GHRIDgroup maintained ΔheightSDS within ±0.3 vs 41% in the GHUIDgroup (P = 0.0055) and 48% in the GHFIXgroup (P = 0.0047). The ΔIGF-ISDS in the GHRID group was -0.75 ± 1.0 at 3 months (P = 0.003) and -0.72 ± 1.2 at 1 year compared with the GHUID group (0.15 ± 1.2; P = 0.005) and GHFIX group (0.05 ± 1.0; P = 0.02). Conclusions Channel parallel growth (i.e., normal height velocity) and IGF-ISDS levels within ±2 were maintained after completed CUG using a 50% lower individualized dose than that used during the CUG period.

ORIGINAL ARTICLE: Metabolic outcome of GH treatment in prepubertal short children with and without classical GH deficiency: Dissociation of anabolic and lipolytic GH effects

Context  Few studies have evaluated the metabolic outcomes of growth hormone (GH) treatment in idiopathic short stature (ISS). Moreover, children with ISS appear to need higher GH doses than children with GH deficiency (GHD) to achieve the same amount of growth and may therefore be at increased risk of adverse events during treatment. The individualized approach using prediction models for estimation of GH responsiveness, on the other hand, has the advantage of narrowing the range of growth response, avoiding too low or high GH doses.