Disorders of ovarian function in childhood and adolescence: evolving needs of the growing child. An endocrine perspective

Hypertension in Turner syndrome: a review of proposed mechanisms, management and new directions

Acquired cardiovascular diseases account for much of the increased risk of premature death in patients with Turner syndrome (TS). Hypertension is a major modifiable cardiovascular risk factor. It has a high prevalence in TS developing at an early age and thus leading to prolonged exposure to high blood pressure. The aetiology for hypertension in TS is largely unknown. It is likely multifactorial, and recent hypotheses include altered sympathetic tone, vasculopathy and endocrine factors. In this review article we aim to provide a comprehensive review of data on mechanisms of hypertension in TS and their implication for diagnostics and optimal choice of antihypertensive treatments. Ultimately this knowledge should help prevent hypertension-related complications, and improve quality of life and life expectancy for patients with TS.

Hormonal replacement therapy in adolescents and young women with chemo- or radio-induced premature ovarian insufficiency: Practical recommendations

In women with premature ovarian insufficiency (POI), hormonal therapy (HT) is indicated to decrease the risk of morbidity and to treat symptoms related to prolonged hypoestrogenism. While general recommendations for the management of HT in adults with POI have been published, no systematic suggestions focused on girls, adolescents and young women with POI following gonadotoxic treatments (chemotherapy, radiotherapy, stem cell transplantation) administered for pediatric cancer are available. In order to highlight the challenging issues specifically involving this cohort of patients and to provide clinicians with the proposal of practical therapeutic protocol, we revised the available literature in the light of the shared experience of a multidisciplinary team of pediatric oncologists, gynecologists and endocrinologists. We hereby present the proposals of a practical scheme to induce puberty in prepubertal girls and a decisional algorithm that should guide the clinician in approaching HT in post-pubertal adolescents and young women with iatrogenic POI.

Effect of Dosage of 17ß-Estradiol on Uterine Growth in Turner Syndrome-A Randomized Controlled Clinical Pilot Trial

CONTEXT

Most Turner syndrome (TS) girls need exogenous estrogen treatment to induce puberty and normal uterine growth. After puberty, the optimal estrogen treatment protocol has not been determined.

OBJECTIVE

To compare 2 doses of oral 17ß-estradiol on uterine size.

DESIGN

A double-blind, 5-year randomized controlled clinical trial.

SETTING

Ambulatory care.

PARTICIPANTS

Twenty young TS women (19.2 ± 2.5 years, range 16.0-24.9) participated. Sixteen patients completed the study. No patients withdrew due to adverse effects.

INTERVENTION

The lower dose (LD) group took 2 mg 17ß-estradiol/d orally and placebo. The higher dose (HD) group took 4 mg 17ß-estradiol/d orally.

MAIN OUTCOME MEASURE(S)

Uterine volume evaluated by transabdominal ultrasound yearly.

RESULTS

Uterine size increased significantly more in the HD group compared with the LD group (P = 0.038), with a gain in uterine volume within the first 3 years of treatment of 19.6 mL (95% confidence interval [CI] = 4.0-19.0) in the HD group compared with 11.5 mL (95% CI = 11.2-27.9) in the LD group. The difference in 3-year gain was 8.1 mL (95% CI = 0.7-15.9). At the last visit, there were no significant differences in uterine volume between the groups.

CONCLUSION

HD oral 17ß-estradiol induces a steeper increase in uterine volume within the first years of treatment compared with the LD. However, the uterine growth potential seems to be the same in most young TS women making the duration of treatment equally significant as estrogen dose, although a few TS women did not experience sufficient uterine growth on 2 mg of estradiol.

CLINICALTRIALS.GOV

NCT00134745Abbreviations: BMI, body mass index; BSA, body surface area; DHEAS, dihydroepiandrosteronesulfate; HD, higher dose; HRT, hormone replacement therapy; LD, lower dose; TS, Turner syndrome; US, ultrasound.

Encapsulation of ovarian allograft precludes immune rejection and promotes restoration of endocrine function in immune-competent ovariectomized mice

Premature ovarian insufficiency (POI) is a significant complication of cytotoxic treatments due to extreme ovarian sensitivity to chemotherapy and radiation. POI is particularly devastating for young girls reaching puberty, because it irreversibly affects their physical and cognitive development. Changes occurring during puberty determine their height, bone health, insulin responsiveness, lipid metabolism, cardiovascular health and cognition. The only available treatment for POI during puberty is hormone replacement therapy (HRT), which delivers non-physiological levels of estrogen, lacks other ovarian hormones and pulsatility, and is not responsive to feedback regulation. Here we report that ovarian allografts encapsulated in a hydrogel-based capsule and implanted in ovariectomized mice restore ovarian endocrine function in immune competent mice. Ovarian tissue from BALB/c mice was encapsulated in poly(ethylene-glycol) (PEG) hydrogels, with a proteolytically degradable core and a non-degradable shell. The dual capsules were implanted subcutaneously in immune competent ovariectomized C57BL/6 mice for a period of 60 days. As expected, non-encapsulated ovarian allografts implanted in a control group sensitized the recipients as confirmed with donor-specific IgG in the serum, which increased 26-fold in the 3 weeks following transplantation (p = 0.02) and infiltration of the graft with CD8 T cells consistent with allo-immunity. In contrast, encapsulation in the Dual PEG capsules prevented sensitization to the allograft in all the recipients with no evidence of lymphocytic infiltration. In summary, the approach of hydrogel-based immunoisolation presents a minimally invasive and robust cell-therapy to restore hormonal balance in ovarian insufficiency. This report is the first to demonstrate the application of a tunable PEG-based hydrogel as an immunoisolator of allogeneic ovarian tissue to restore endocrine function in ovariectomized mice and prevent cell-mediated immune rejection in immune competent mice.

Primary gonadal failure

The term primary gonadal failure encompasses not only testicular insufficiency in 46,XY males and ovarian insufficiency in 46,XX females, but also those disorders of sex development (DSD) which result in gender assignment that is at variance with the genotype and gonadal type. In boys, causes of gonadal failure include Klinefelter and other aneuploidy syndromes, bilateral cryptorchidism, testicular torsion, and forms of 46,XY DSD such as partial androgen insensitivity. Causes in girls include Turner syndrome and other aneuploidies, galactosemia, and autoimmune ovarian failure. Iatrogenic causes in both boys and girls include the late effects of childhood cancer treatment, total body irradiation prior to bone marrow transplantation, and iron overload in transfusion-dependent thalassaemia. In this paper, a brief description of the physiology of testicular and ovarian development is followed by a section on the causes and practical management of gonadal impairment in boys and girls. Protocols for pubertal induction and post-pubertal hormone replacement - intramuscular, oral and transdermal testosterone in boys; oral and transdermal oestrogen in girls - are then given. Finally, current and future strategies for assisted conception and fertility preservation are discussed.

Pubertal induction in hypogonadism: Current approaches including use of gonadotrophins

Primary disorders of the gonad or those secondary to abnormalities of the hypothalamic pituitary axis result in hypogonadism. The range of health problems of childhood and adolescence that affect this axis has increased, as most children now survive chronic illness, but many have persisting deficits in gonadal function as a result of their underlying condition or its treatment. An integrated approach to hormone replacement is needed to optimize adult hormonal and bone health, and to offer opportunities for fertility induction and preservation that were not considered possible in the past. Timing of presentation ranges from birth, with disorders of sexual development, through adolescent pubertal failure, to adult fertility problems. This review addresses diagnosis and management of hypogonadism and focuses on new management strategies to address current concerns with fertility preservation. These include Turner syndrome, and fertility presevation prior to childhood cancer treatment. New strategies for male hormone replacement therapy that may impinge upon future fertility are emphasized.

Endocrine problems in children and adolescents who have disabilities

The consequences of disability span almost all aspects of life, for families and for an affected individual. Endocrine aspects of disability cover disorders of hypothalamic pituitary dysfunction, bone health, puberty, fertility, sexual function and contraceptive needs. Adequate endocrine assessment for a child with a disability requires extensive and sensitive history to address social issues, general nutrition, vitamin D status, specific hypothalamic pituitary problems, together with parental concerns regarding puberty and contraception. Bone health assessment includes history of minimal trauma fracture, need for intervention or fitness for surgery. Strategic interventions to improve outcome include management of puberty, vitamin D status, biomechanical stimulation with vibration and standing and possible consideration for bisphosphonate in special circumstances. Both early and late puberty cause major family concerns. The paediatrician must be aware of a range of management options to improve outcomes for the child and family.

[Cryopreserved ovaries: models of experimental grafting]

Childhood cancers account for 1% of malignant tumors. As a result of advances in treatment, almost 80% of children and adolescents who currently receive a diagnosis of cancer become long-term survivors. Assessment of potential for fertility preservation should thus be a systematic element of care for children treated for a malignant tumor (high-dose chemotherapy with alkylizing agents, radiation therapy including the gonads) or those receiving hematopoietic stem cell grafts for malignant or benign disease (sickle-cell anemia, immune deficit). Potential adverse consequences of treatment include impaired puberty and fertility due to gonadal removal, genital tract injury or damage to germ cells from adjuvant therapy. Advances in assisted reproductive technologies have led to new possibilities for the prevention and treatment of infertility. Among them, cryopreservation of ovarian tissue appears to be the most promising, or perhaps the only one available before puberty with encouraging results. Nevertheless the uncertainties, or even risks, related to these treatments, should not be neglected. We review experimental data in mouse and sheep animal models. The results demonstrate that immature ovarian grafting can restore spontaneous puberty and fertility in both models. This study addresses the very important issue of epigenetics, and provides valuable information for the study of ovarian transplantation, suggesting that these procedures do not perturb normal epigenetic marks. These results are highly relevant to the question of immature cortex reimplantation.