Long-term effects of growth hormone treatment on height in Turner syndrome: results of a 6-year multicentre study in Japan. Committee for the Treatment of Turner Syndrome

Human Growth and Growth Hormone: From Antiquity to the Recominant Age to the Future

Since antiquity Man has been fascinated by the variations in human (and animal) growth. Stories and art abound about giants and little people. Modern genetics have solved some of etiologies at both extremes of growth. Serious study began with the pathophysiology of acromegaly followed by early attempts at treatment culminating in modern endoscopic surgery and multiple pharmacologic agents. Virtually at the same time experiments with the removal of the pituitary from laboratory animals noted the slowing or stopping of linear growth and then over a few decades the extraction and purification of a protein within the anterior pituitary that restored, partially or in full, the animal's growth. Human growth hormone was purified decades after those from large animals and it was noted that it was species specific, that is, only primate growth hormone was metabolically active in primates. That was quite unlike the beef and pork insulins which revolutionized the care of children with diabetes mellitus. A number of studies included mild enzymatic digestion of beef growth hormone to determine if those "cores" had biologic activity in primates and man. Tantalizing data showed minimal but variable metabolic efficacy leading to the "active core" hypothesis, for these smaller peptides would be amenable to peptide synthesis in the time before recombinant DNA. Recombinant DNA changed the landscape remarkably promising nearly unlimited quantities of metabolically active hormone. Eight indications for therapeutic use have been approved by the Food and Drug Administration and a large number of clinical trials have been undertaken in multiple other conditions for which short stature in childhood is a sign. The future predicts other clinical indications for growth hormone therapy (and perhaps other components of the GH?IGF-1 axis), longer-acting analogues and perhaps a more physiologic method of administration as virtually all methods at present are far from physiologic.

Effect of oxandrolone and timing of pubertal induction on final height in Turner's syndrome: randomised, double blind, placebo controlled trial

OBJECTIVE

To examine the effect of oxandrolone and the timing of pubertal induction on final height in girls with Turner's syndrome receiving a standard dose of growth hormone.

DESIGN

Randomised, double blind, placebo controlled trial. Setting 36 paediatric endocrinology departments in UK hospitals.

PARTICIPANTS

Girls with Turner's syndrome aged 7-13 years at recruitment, receiving recombinant growth hormone therapy (10 mg/m(2)/week).

INTERVENTIONS

Participants were randomised to oxandrolone (0.05 mg/kg/day, maximum 2.5 mg/day) or placebo from 9 years of age. Those with evidence of ovarian failure at 12 years were further randomised to oral ethinylestradiol (year 1, 2 µg daily; year 2, 4 μg daily; year 3, 4 months each of 6, 8, and 10 μg daily) or placebo; participants who received placebo and those recruited after the age of 12.25 years started ethinylestradiol at age 14.

MAIN OUTCOME MEASURE

Final height. Results 106 participants were recruited, of whom 14 withdrew and 82/92 reached final height. Both oxandrolone and late pubertal induction increased final height: by 4.6 (95% confidence interval 1.9 to 7.2) cm (P = 0.001, n = 82) for oxandrolone and 3.8 (0.0 to 7.5) cm (P = 0.05, n = 48) for late pubertal induction with ethinylestradiol. In the 48 children who were randomised twice, the effects on final height (compared with placebo and early induction of puberty) of oxandrolone alone, late induction alone, and oxandrolone plus late induction were similar, averaging 7.1 (3.4 to 10.8) cm (P < 0.001). No cases of virilisation were reported.

CONCLUSION

Oxandrolone had a positive effect on final height in girls with Turner's syndrome treated with growth hormone, as did late pubertal induction with ethinylestradiol at age 14 years. However, these effects were not additive, so using both had no advantage. Oxandrolone could, therefore, be offered as an alternative to late pubertal induction for increasing final height in Turner's syndrome. Trial registration Current Controlled Trials ISRCTN50343149.

Growth-promoting effect of recombinant human growth hormone and stanozolol in girls with Turner syndrome

Ten girls with Turner syndrome were treated with a combination therapy of recombinant human growth hormone (R-hGH) and low dose stanozolol for a period of 8 to 36 months. The results showed that when compared with the growth rate before the treatment, the growth rates after treatment with R-hGH and stanozolol showed a sustained increase, reaching 9.0 +/- 1.9 cm/year during the first year of treatment; the height age increase by 2.5 +/- 0.8 years while the bone age increase were 1.0 +/- 0.7 years; and the predicted final adult height at the end of the first year of the treatment increased to 149.4 +/- 6.1 cm compared to their original mean of 142.8 +/- 4.2 cm. We are led to conclude that therapy with R-hGH in combination with stanozolol can increase the growth velocity and significantly increase the predicted adult height of children with Turner syndrome.

Role of oestrogen therapy in the management of short stature in Turner syndrome

It is now clear that parenteral growth hormone (GH) therapy stimulates growth and increases the adult stature of girls with Turner syndrome. In addition, oestrogens are given to almost all girls with this syndrome because of primary hypogonadism. Oestrogens influence both growth and maturation of the epiphyseal growth plates. Therefore, the form and timing of oestrogen therapy may have an important impact on the outcome of other growth-promoting therapies. To examine the impact of the timing of oestrogen initiation on growth, a randomized trial was conducted in patients with Turner syndrome who were receiving GH. Some patients received oestrogen at 12 years of age, while in others this treatment was not started until 15 years of age. Those girls that received oestrogen later were significantly taller as adults. The single most important factor in determining height gain appeared to be the number of years of GH therapy prior to the initiation of oestrogen treatment.

The growth pattern and final height of girls with Turner syndrome with and without human growth hormone treatment

BACKGROUND

Shortness is the most frequent and quite disturbing characteristic of girls with Turner syndrome (TS). Human growth hormone administration (hGH) to girls with TS increases growth velocity (GV), but a favorable effect on final height (FH) has not been documented. The aim of this study was to evaluate the effect of hGH administration on the growth pattern and FH in girls with TS.

METHODS

The study group was comprised of 123 girls with TS who were cared for in our center. Eighty-two of these girls received hGH (mean dose, 0.78 +/- 0.12 IU/kg/week), given subcutaneously 5 to 7 times per week for a period of 2.2 +/- 1.2 years (hGH group). The mean chronological age (CA) and bone age (BA) at hGH initiation were 11.5 +/- 2.5 years and 9.7 +/- 2.3 years, respectively. The remaining 41 girls did not receive hGH and are designated as the untreated control group. In both groups, gonadal steroids were given for pubertal initiation and maintenance.

RESULTS

The GV during the first year of hGH therapy (GV1) was higher than the year before hGH (6.3 cm/year vs 4.0 cm/year) and higher than the GV of the untreated group at a similar CA (4.4 cm/year). The GVs during the second (GV2) and third (GV3) year of hGH treatment (5.4 and 4.9 cm/year, respectively) were lower, but still higher in the hGH group, in comparison with the untreated group (GV2, 4.2 cm/year; GV3, 3.4 cm/year). GV1, GV2, and GV3 were negatively related to age and to BA at hGH initiation. The FH of the 35 hGH-treated girls was not significantly different from the FH of the 27 untreated girls (146.1 cm vs 144.0 cm). The Delta target height-FH was not significantly different in the two groups. The FH standard deviation score of the hGH-treated group was positively related to height standard deviation score for CA at treatment initiation (r = +0.73), maternal height (r = +0.57), target height (r = + 0.66), and birth weight (r = +0.54), but was unrelated to CA or BA at start of therapy or to hGH dose.

CONCLUSIONS

hGH therapy in girls with TS, in the dose and duration of treatment applied in this study, significantly accelerated GV but did not significantly improve FH.

Variable effect of growth hormone on growth and final adult height in Scottish patients with Turner's syndrome

The aim of this work was to assess the outcome of recombinant growth hormone (rGH) therapy in a large unselected group (72) of patients with Turner's syndrome (TS), 26 of whom have reached final height. Growth data were collected from Scottish patients with TS and outcome was assessed in three ways: response to therapy in the first year, response in subsequent years and final height. Phenotypic, auxological, genetic and biochemical factors, all of which may have affected the first-year response, were investigated. Fifty-one percent of the cohort had a clinically "good" first-year response to therapy and 49% had a "poor" response, a "good" response was defined as a change in the TS standard deviation score (SDS) of +0.5 or more and a "poor" response as a change in the TS SDS of less than +0.5. The percentage of children showing a positive change in TS SDS after 2, 3 and 4 years of therapy declined (88%, 78%, 41%). Mean (range) final height was 142.6 (133.4-153.6) cm, mean (range) pretreatment TS SDS was -0.27 (-2.1 to +1.09) and mean (range) final TS SDS was -0.05 (-1.4 to +1.59). Thirteen (50%) patients attained a final height that was greater than projected, eleven did not attain their projected final height and two achieved their exact projected final height. Short girls with TS appear to benefit more from rGH supplementation than tall girls, but otherwise there was no significant correlation between any of the parameters studied and the response to treatment. It is concluded that large-scale prospective studies are still required to assess the impact of rGH on final height in TS and to identify factors responsible for the variability in response.

Growth hormone treatment in Noonan syndrome

Growth responses to growth hormone (GH) treatment in Noonan syndrome are compared with those in short children with the other growth disorders. The responses in Noonan syndrome are much less than those in children with GH deficiency, a little less than those in children with non-endocrine short stature and almost the same as those in children with Turner syndrome. As it is speculated that GH induces puberty earlier that expected in Noonan Syndrome, the efficiency of GH treatment for final height in Noonan syndrome is not promising.