Recombinant human growth hormone in the treatment of Turner syndrome

Magnetically actuating implantable pump for the on-demand and needle-free administration of human growth hormone

A bolus of human growth hormone (hGH) is often prescribed for the treatment of growth hormone deficiency, which requires frequent injections in current clinical settings. This painful needle-involved delivery often results in poor patient compliance, leading to low medication adherence and poor clinical outcomes. Therefore, we propose a magnetically actuating implantable pump (MAP) that can infuse an accurate dose of hGH only at the time of non-invasive magnet application from the skin. The MAP herein could reproducibly infuse 20.6 ± 0.9 μg hGH per actuation without any leak at times without actuation. The infused amount increased proportionally with an increase in the number of actuations. When the MAP was implanted and actuated with a magnet in animals with growth hormone deficiency for 21 days, the profiles of plasma hGH concentration and insulin-like growth factor (IGF)-1, as well as changes in body weight, were similar to those observed in animals treated with conventional subcutaneous hGH injections. Therefore, we anticipate that the MAP fabricated in this study can be a non-invasive alternative to administer hGH without repeated and frequent needle injections.

Origin of the X-chromosome influences the development and treatment outcomes of Turner syndrome

Turner syndrome (TS) affects 1/2,500 live-born female infants. In the present study, we attempted to clarify the relationship between genetic factors (especially the X-chromosome origin), clinical features, body/sexual development, and treatment outcomes. We enrolled 39 female infants aged between 3 and 14 years. General demographic and clinical features were documented, and laboratory analysis of blood samples was performed. Subject karyotype was determined by G-banding of 50 peripheral white blood cells, and the parenteral origin of the retained X-chromosome was determined. Next, growth hormone (GH) treatment was prescribed for 12 months, with follow-ups performed as determined. For patient groups separated according to X-chromosome origin, the basal height, bone age, insulin-like growth factor (IGF)-1, and insulin-like growth factor binding protein-3 (IGFBP-3) levels were comparable; however, after the 12-month treatment, significant differences in the height increase and IGF-1 levels were observed. If the X-chromosome (or chromosomes) originated from both parents, the increase in height was less substantial, with lower serum IGF-1 levels. The uterine size, prolactin level, increased weight after treatment, and bone age difference after treatment negatively correlated with the mother’s age at the time of birth. The mother’s height at the time of birth demonstrated a negative correlation with the basal bone age difference and a positive correlation with the IGF-1 level. In summary, the retained X-chromosome derived from both parents is associated with poorer response to GH therapy. The mother’s age and height at the time of birth can strongly impact the patient’s body/sexual development and the response to GH treatment. Thus, the mother’s age and height at the time of birth and the parental origin of the X-chromosome should be carefully considered before developing a treatment plan for TS.

Prevention of Growth Failure in Turner Syndrome: Long-Term Results of Early Growth Hormone Treatment in the "Toddler Turner" Cohort

INTRODUCTION

In the randomized "Toddler Turner" study, girls who received growth hormone (GH) starting at ages 9 months to 4 years (early-treated [ET] group) had marked catch-up growth and were 1.6 ± 0.6 SD taller than untreated (early-untreated [EUT]) control girls after 2 years. However, whether the early catch-up growth would result in greater near-adult height (NAH) was unknown. Therefore, this extension study examined the long-term effects of toddler-age GH treatment on height, pubertal development, and safety parameters.

METHODS

Toddler Turner study participants were invited to enroll in a 10-year observational extension study for annual assessments of growth, pubertal status, and safety during long-term GH treatment to NAH for both ET and EUT groups.

RESULTS

The ET group was taller than the EUT group at all time points from preschool to maturity and was significantly taller at the onset of puberty (p = 0.016), however, the difference was not significant at NAH. For the full cohort (ET + EUT combined, n = 50) mean (± SD) NAH was 151.2 ± 7.1 cm at age 15.0 ± 1.3 years. NAH standard deviation score (SDS) was within the normal range (>-2.0) for 76% of ET and 60% of EUT subjects (68% overall) and correlated strongly with height SDS at GH start (r = 0.78; p < 0.01), which in turn had a modest inverse correlation with age at GH start (i.e., height SDS declined with increasing age in untreated girls [r = -0.30; p = 0.016]). No new safety concerns arose.

CONCLUSION

Although the ET group was taller throughout, height SDS at NAH was not significantly different between groups due to catch-down growth of ET girls during lapses in GH treatment after the Toddler study and similar long-term GH exposure overall. Early initiation of GH by age 6 years, followed by uninterrupted treatment during childhood, can prevent ongoing growth failure and enable attainment of height within the normal range during childhood, adolescence, and adulthood.

The influence of growth hormone therapy on the cardiovascular system in Turner syndrome

Short stature, ovarian dysgenesis, infertility, and cardiovascular malformations are classic features in Turner syndrome (TS), but the phenotypical spectrum is wide. Through early diagnosis and appropriate treatment, TS patients have a chance to achieve satisfactory adult height and sexual development. The doses of recombinant growth hormone (rGH) used are usually higher than the substitution dose. The safety aspects of this therapy are very important, especially in terms of the cardiovascular system. The presented study aimed to analyze how the rGH therapy may influence the cardiovascular system in TS based on current literature data. We conducted a systematic search for studies related to TS, cardiovascular system, and rGH therapy. The results show that rGH seems to have a positive effect on lipid parameters, reducing the risk of ischemic disease. It is additionally optimized by estradiol therapy. Although rGH may increase insulin resistance, the metabolic derangement is rare, probably due to lower fat content and an increase in lean body mass. Several studies showed that rGH treatment could cause aorta widening or increase the aorta growth rate. IGF-1 can be independently associated with increased aortic diameters. The studies analyzing the impact of GH on blood pressure show conflicting data. The proper cardiovascular imaging before and during rGH treatment and detecting the known risk factors for aorta dissection in every individual is very important. The long-term effects of growth hormone treatment on the heart and arteries are still not available and clearly estimated and have to be monitored in the future.

Characterization of a novel method for the production of single-span membrane proteins in Escherichia coli

The large‐scale production and isolation of recombinant protein is a central element of the biotechnology industry and many of the products have proved extremely beneficial for therapeutic medicine. Escherichia coli is the microorganism of choice for the expression of heterologous proteins for therapeutic application, and a range of high‐value proteins have been targeted to the periplasm using the well characterized Sec protein export pathway. More recently, the ability of the second mainstream protein export system, the twin‐arginine translocase, to transport fully‐folded proteins into the periplasm of not only E. coli, but also other Gram‐negative bacteria, has captured the interest of the biotechnology industry.

In this study, we have used a novel approach to block the export of a heterologous Tat substrate in the later stages of the export process, and thereby generate a single‐span membrane protein with the soluble domain positioned on the periplasmic side of the inner membrane. Biochemical and immuno‐electron microscopy approaches were used to investigate the export of human growth hormone by the twin‐arginine translocase, and the generation of a single‐span membrane‐embedded variant. This is the first time that a bonafide biotechnologically relevant protein has been exported by this machinery and visualized directly in this manner. The data presented here demonstrate a novel method for the production of single‐span membrane proteins in E. coli.

Still too little, too late? Ten years of growth hormone therapy baseline data from the NordiNet® International Outcome Study

BACKGROUND

We investigated time trends in age, gender, growth hormone (GH) dose and height standard deviation score (SDS) in children with GH deficiency (GHD), born small for gestational age (SGA) or with Turner syndrome (TS) starting GH treatment.

METHODS

Data were obtained from children enrolled in the NordiNet® International Outcome Study (IOS) between 2006 and 2015 in the Czech Republic, France, Germany, Serbia and Montenegro (all indications), and Switzerland and the UK (GHD only). Trends were analyzed by linear regression. Patients were divided by age into early-, medium- or late-start groups in three different time periods.

RESULTS

Approximately one-third of children starting treatment for GHD were girls, with no apparent increase in proportion over time. The mean baseline age for starting treatment decreased significantly (p<0.001) for both GHD and SGA in the Czech Republic and Germany. In the other countries studied, over 40% of children started treatment for GHD and SGA late (girls >10, boys >11 years) between 2013 and 2015. The mean baseline GH doses were largely within recommended ranges for GHD and SGA, but below the lowest recommended starting dose for TS in almost every year since 2011 except in France.

CONCLUSIONS

Approximately one-third of children starting treatment for GHD were girls. Between 2013 and 2015, more than 40% of children started treatment for GHD and SGA late except in Germany and the Czech Republic. TS patients received below-recommended doses. These results highlight the need for earlier identification of short stature in children, particularly girls, and for dose optimization in TS.

Skin manifestations of growth hormone-induced diseases

The human skin is a well-organized organ bearing different types of cells in a well-structured interference to each other including epidermal and follicular keratinocytes, sebocytes, melanocytes, dermal papilla cells and fibroblasts, endothelial cells, sweat gland cells as well as nerves. Several hormones act on different cell types of the skin, while it is also considered an endocrine organ secreting hormones that act at several sites of the organism. GH receptors are found in almost all cell types forming the skin, while IGF-1 receptors' expression is restricted to the epidermal keratinocytes. Both Growth Hormone (GH) excess, as in the case of Acromegaly in adults, or Gigantism in growing children, and GH deficiency states lead to skin manifestations. In case of GH excess the main dermatological findings are skin thickening, coarsening of facial features, acrochordons, puffy hands and feet, oily skin and hyperhidrosis, while GH deficiency, on the contrary, is characterized by thin, dry skin and disorder of normal sweating. Moreover, special disorders associated with GH excess may have specific characteristics, as is the case of café-au-lait spots in Neurofibromatosis, or big café-au-lait skin hyperpigmented regions with irregular margins, as is the case in McCune-Albright syndrome. Meticulous examination of the skin may therefore contribute to the final diagnosis in cases of GH-induced disorders.

Response to three years of growth hormone therapy in girls with Turner syndrome

PURPOSE

Short stature is the most common finding in patients with Turner syndrome. Improving the final adult height in these patients is a challenge both for the patients and physicians. We investigated the clinical response of patients to growth hormone treatment for height improvement over the period of three years.

METHODS

Review of medical records from 27 patients with Turner syndrome treated with recombinant human growth hormone for more than 3 years was done. Differences in the changes of height standard deviation scores according to karyotype were measured and factors influencing the height changes were analyzed.

RESULTS

The response to recombinant human growth hormone was an increase in the height of the subjects to a mean value of 1.1 standard deviation for subjects with Turner syndrome at the end of the 3-year treatment. The height increment in the first year was highest. The height standard deviation score in the third year was negatively correlated with the age at the beginning of the recombinant human growth hormone treatment. Different karyotypes in subjects did not seem to affect the height changes.

CONCLUSION

Early growth hormone administration in subjects with Turner syndrome is helpful to improve height response to the treatment.

An observational study of the effectiveness and safety of growth hormone (Humatrope(®)) treatment in Japanese children with growth hormone deficiency or Turner syndrome

This study assessed the effectiveness and safety of growth hormone (GH; Humatrope(®)) therapy in Japanese children with GH deficiency (GHD) or Turner syndrome (TS) enrolled in the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS). GeNeSIS is an open-label, multinational, multicenter, observational study conducted in 30 countries. In this interim report, there were 1129 GH treatment-naïve children with GHD, with a mean chronological age (± standard deviation) of 8.75 (3.32) years, and 90 girls with TS, with a mean chronological age of 8.93 (3.67) years. The mean height standard deviation score (SDS) increased from -2.73 (0.63) SD and -2.71 (0.63) SD at study entry to -2.22 (0.68) SD and -2.20 (0.60) SD after 1 year of treatment in the GHD and TS groups, respectively. In both groups, mean height SDS increased further with each year of treatment to 4 years; however, the magnitude of change in height SDS declined with time. The mean insulin-like growth factor-I SDS increased from below the mean of the reference population at study entry to a level similar to (GHD group) or higher than (TS group) the mean of the reference population during the 4-year treatment period. The incidence of serious adverse events (AEs), treatment-related AEs, and AEs related to glucose intolerance was low in both groups (0.1% to 3.0%). In conclusion, GH treatment in Japanese children with GHD or TS resulted in increased growth over a 4-year treatment period with a favorable safety profile; however, the improvements in growth declined with time.

Update on Turner and Noonan syndromes

Turner syndrome (TS) and Noonan syndrome (NS) have short stature as a constant feature; however, both conditions can present clinicians with a challenging array of genetic, cardiovascular, developmental, and psychosocial issues. In recent years, important advances have been achieved in each of these areas. This article reviews these two syndromes and provides updates on recent developments in diagnostic evaluation, growth and development, psychological issues, and treatment options for patients with TS and NS.

Short stature and its treatment in Turner and Noonan syndromes

PURPOSE OF REVIEW

We review recent developments in the approach to the treatment of short stature in patients with Turner and Noonan syndromes.

RECENT FINDINGS

Turner syndrome and Noonan syndrome are clinically defined conditions associated with short stature. The Food and Drug Administration (FDA) approved treatment with recombinant human growth hormone (hGH) for patients with Turner syndrome in 1996 and for those with Noonan syndrome in 2007. Studies have shown that early appropriate use of hGH increases adult height in individuals with Turner syndrome. The combination of hGH and low-dose estrogen may also improve growth and adult height as well as possibly provide neurocognitive and behavioral benefits. Noonan syndrome is a genetically heterogeneous condition. In patients with Noonan syndrome phenotype, investigators have identified disease-associated genes (PTPN11, SOS1, RAF1, KRAS, and others). Treatment with hGH has been documented to result in short-term increases in growth velocity as well as modest gains in adult height.

SUMMARY

Our understanding and management of short stature in children with Turner syndrome and Noonan syndrome has greatly advanced over the years. Recent developments with focus on these two common syndromes will be reviewed.