Estrogens and selective estrogen receptor modulators in acromegaly

Diagnosis and Management of Aggressive/Refractory Growth Hormone-Secreting Pituitary Neuroendocrine Tumors

The majority of acromegaly and gigantism are caused by growth hormone-secreting pituitary neuroendocrine tumors (PitNETs). Most cases can be cured or controlled by surgery, medical therapy, and/or radiotherapy. However, a few of these tumors are resistant to traditional therapy and always have a poor prognosis. The title aggressive/refractory is used to differentiate them from pituitary carcinomas. To date, there is no definitive conclusion on how to diagnose aggressive/refractory growth hormone-secreting PitNETs, which may have slowed the process of exploring new therapeutical strategies. We summarized the literature described diagnosis and treatment of the disease. Potential disease markers and prospective therapies were also included.

Role of Estrogen and Estrogen Receptor in GH-Secreting Adenomas

Acromegaly is a rare disease with several systemic complications that may lead to increased overall morbidity and mortality. Despite several available treatments, ranging from transsphenoidal resection of GH-producing adenomas to different medical therapies, complete hormonal control is not achieved in some cases. Some decades ago, estrogens were first used to treat acromegaly, resulting in a significant decrease in IGF1 levels. However, due to the consequent side effects of the high dose utilized, this treatment was later abandoned. The evidence that estrogens are able to blunt GH activity also derives from the evidence that women with GH deficiency taking oral estro-progestins pills need higher doses of GH replacement therapy. In recent years, the role of estrogens and Selective Estrogens Receptor Modulators (SERMs) in acromegaly treatment has been re-evaluated, especially considering poor control of the disease under first- and second-line medical treatment. In this review, we analyze the state of the art concerning the impact of estrogen and SERMs on the GH/IGF1 axis, focusing on molecular pathways and the possible implications for acromegaly treatment.

Is Hormone Replacement Therapy a Risk Factor or a Therapeutic Option for Alzheimer's Disease?

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for more than half of all dementia cases in the elderly. Interestingly, the clinical manifestations of AD disproportionately affect women, comprising two thirds of all AD cases. Although the underlying mechanisms for these sex differences are not fully elucidated, evidence suggests a link between menopause and a higher risk of developing AD, highlighting the critical role of decreased estrogen levels in AD pathogenesis. The focus of this review is to evaluate clinical and observational studies in women, which have investigated the impact of estrogens on cognition or attempted to answer the prevailing question regarding the use of hormone replacement therapy (HRT) as a preventive or therapeutic option for AD. The articles were retrieved through a systematic review of the databases: OVID, SCOPUS, and PubMed (keywords "memory", "dementia," "cognition," "Alzheimer's disease", "estrogen", "estradiol", "hormone therapy" and "hormone replacement therapy" and by searching reference sections from identified studies and review articles). This review presents the relevant literature available on the topic and discusses the mechanisms, effects, and hypotheses that contribute to the conflicting findings of HRT in the prevention and treatment of age-related cognitive deficits and AD. The literature suggests that estrogens have a clear role in modulating dementia risk, with reliable evidence showing that HRT can have both a beneficial and a deleterious effect. Importantly, recommendation for the use of HRT should consider the age of initiation and baseline characteristics, such as genotype and cardiovascular health, as well as the dosage, formulation, and duration of treatment until the risk factors that modulate the effects of HRT can be more thoroughly investigated or progress in the development of alternative treatments can be made.

Approach of Acromegaly during Pregnancy

Acromegaly-related sub/infertility, tidily related to suboptimal disease control (1/2 of cases), correlates with hyperprolactinemia (1/3 of patients), hypogonadotropic hypogonadism—mostly affecting the pituitary axis in hypopituitarism (10−80%), and negative effects of glucose profile (GP) anomalies (10−70%); thus, pregnancy is an exceptional event. Placental GH (Growth Hormone) increases from weeks 5−15 with a peak at week 37, stimulating liver IGF1 and inhibiting pituitary GH secreted by normal hypophysis, not by somatotropinoma. However, estrogens induce a GH resistance status, protecting the fetus form GH excess; thus a full-term, healthy pregnancy may be possible. This is a narrative review of acromegaly that approaches cardio-metabolic features (CMFs), somatotropinoma expansion (STE), management adjustment (MNA) and maternal-fetal outcomes (MFOs) during pregnancy. Based on our method (original, in extenso, English—published articles on PubMed, between January 2012 and September 2022), we identified 24 original papers—13 studies (3 to 141 acromegalic pregnancies per study), and 11 single cases reports (a total of 344 pregnancies and an additional prior unpublished report). With respect to maternal acromegaly, pregnancies are spontaneous or due to therapy for infertility (clomiphene, gonadotropins or GnRH) and, lately, assisted reproduction techniques (ARTs); there are no consistent data on pregnancies with paternal acromegaly. CMFs are the most important complications (7.7−50%), especially concerning worsening of HBP (including pre/eclampsia) and GP anomalies, including gestational diabetes mellitus (DM); the best predictor is the level of disease control at conception (IGF1), and, probably, family history of 2DM, and body mass index. STE occurs rarely (a rate of 0 to 9%); some of it symptoms are headache and visual field anomalies; it is treated with somatostatin analogues (SSAs) or alternatively dopamine agonists (DAs); lately, second trimester selective hypophysectomy has been used less, since pharmaco-therapy (PT) has proven safe. MNA: PT that, theoretically, needs to be stopped before conception—continued if there was STE or an inoperable tumor (no clear period of exposure, preferably, only first trimester). Most data are on octreotide > lanreotide, followed by DAs and pegvisomant, and there are none on pasireotide. Further follow-up is required: a prompt postpartum re-assessment of the mother’s disease; we only have a few data confirming the safety of SSAs during lactation and long-term normal growth and developmental of the newborn (a maximum of 15 years). MFO seem similar between PT + ve and PT − ve, regardless of PT duration; the additional risk is actually due to CMF. One study showed a 2-year median between hypophysectomy and pregnancy. Conclusion: Close surveillance of disease burden is required, particularly, concerning CMF; a personalized approach is useful; the level of statistical evidence is expected to expand due to recent progress in MNA and ART.

Management of hypopituitarism: a perspective from the Brazilian Society of Endocrinology and Metabolism

Hypopituitarism is a disorder characterized by insufficient secretion of one or more pituitary hormones. New etiologies of hypopituitarism have been recently described, including head trauma, cerebral hemorrhage, and drug-induced hypophysitis. The investigation of patients with these new disorders, in addition to advances in diagnosis and treatment of hypopituitarism, has increased the prevalence of this condition. Pituitary hormone deficiencies can induce significant clinical changes with consequent increased morbidity and mortality rates, while hormone replacement based on current guidelines protects these patients. In this review, we will first discuss the different etiologies of hypopituitarism and then address one by one the clinical aspects, diagnostic evaluation, and therapeutic options for deficiencies of TSH, ACTH, gonadotropin, and GH. Finally, we will detail the hormonal interactions that occur during replacement of pituitary hormones.

The significance of estrogen receptors in acromegaly: Are they useful as predictors of prognosis and therapy regimen?

OBJECTIVE

In this study, we considered to assess the presence of estrogen receptors (ER) and the expression of estrogen receptor genes (ESR) in the surgical tissue samples of acromegaly patients and the control group patients with nonfunctioning adenoma and their association with disease activity. We also aimed to determine the significance of ER positivity in acromegaly patients and to find out whether it carries a potential to be used as a predictor of prognosis and therapy regimen in the future.

DESIGN

This study was conducted on a total of 67 patients over 18 years of age. The study group consisted of 34 patients with acromegaly and 33 patients with nonfunctioning pituitary adenoma. The pre- and post-operative basal pituitary hormone levels and magnetic resonance images (MRI) of all patients, as well as their remission status of all acromegaly patients were evaluated. Immunohistochemical (IHC) staining procedures for ER-α were performed on surgical tissue samples. Real-time quantitative polymerase chain reaction (RT-qPCR) method was used to determine the levels of ESR1 and ESR2 gene expressions.

RESULTS

We found that IHC staining for ER-α was positive in 31.3% and 45.5% of the patients with acromegaly and nonfunctioning adenoma respectively. There was no statistically significant difference of ER-α positivity, ER-α immunoreactivity score and ESR1/ESR2 gene expression levels among the study groups (p > .05). Nevertheless, the expression of ESR1 gene was found to be 0.26 times more, and the ESR2 gene to be 0.11 times less in the acromegaly group compared to those of the nonfunctioning adenoma group. Additionally, we detected the positivity of ER-α only in acromegaly patients who were in remission. An inverse association was found between the pre-operative insulin-like growth factor-1 (IGF-1) levels and the expressions of ESR1/ESR2 gene in acromegaly patients. So these results indicated that the high ESR1 and ESR2 gene expressions in acromegaly patients are associated to the decrease of pre-operative IGF-1 values. Also an inverse association was found between the pre-operative adenoma volume and ESR1 Ct values, means that increase in ESR1 gene expression is associated to the decrease of adenoma volume.

CONCLUSIONS

The current results may suggest the use of these parameters as useful prognostic markers because all ER-positive acromegaly patients were in remission and the high ESR1 and ESR2 gene expressions in acromegaly patients is associated to the decrease of pre-operative IGF-1 values. Our results need to be supported by further studies.

Gender differences and temporal trends over two decades in acromegaly: a single center study in 112 patients

PURPOSE

To evaluate the impact of gender and year at surgery on clinical presentation and postoperative outcomes in acromegaly.

METHODS

Retrospective review of patients operated between 1994 and 2016 to compare presentation and outcomes in groups defined by gender and year of surgery. Kaplan-Meier survival analyses with a composite endpoint (recurrence, reoperation, and radiation) were used for gender comparison and Youden indices for biochemical remission rates changes during study period.

RESULTS

Primary indications for evaluation were phenotype, neurological symptoms, incidentaloma, hypogonadism, and galactorrhea. At surgery, men (N = 54) were younger (43.6 ± 12.7 years) than women (N = 58, 48.7 ± 12.3, P = 0.04). Male:female ratios before and after age 50 were 1.4 and 0.6 respectively. Men had higher mean IGF-1 levels (874 ± 328 vs 716 ± 296, P < 0.01) and smaller tumors (1.8 ± 1.3 cm vs 2.3 ± 1.5, P = 0.04). Postoperative remission rates were comparable (51% men, 56% women) and inversely associated with cavernous sinus invasion and GH levels. Women had longer mean follow-up (5.2 ± 3.4 years vs 3.6 ± 3.6 men, P = 0.02) and longer endpoint-free survival (P < 0.01). At last follow-up, 89.6% women and 70% men had normal IGF-1 levels (P = 0.03). Postoperative remission rates were higher in patients operated after February 15, 2011 (67.35 vs 43.5% previously, P = 0.01). In late vs early surgery group, physical changes as main indication for screening decreased (54 vs 30%, P < 0.01), while incidentaloma and hypogonadism increased. Median GH levels were lower in late vs early surgery group (P = 0.03).

CONCLUSION

We demonstrate gender-specific characteristics and an evolving spectrum of clinical presentation with implications for earlier diagnosis and personalized management of acromegaly.

Acromegaly

Acromegaly is characterized by increased release of growth hormone and, consequently, insulin-like growth factor I (IGF1), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Although considered a rare disease, recent studies have reported an increased incidence of acromegaly owing to better disease awareness, improved diagnostic tools and perhaps a real increase in prevalence. Acromegaly treatment approaches, which include surgery, radiotherapy and medical therapy, have changed considerably over time owing to improved surgical procedures, development of new radiotherapy techniques and availability of new medical therapies. The optimal use of these treatments will reduce mortality in patients with acromegaly to levels in the general population. Medical therapy is currently an important treatment option and can even be the first-line treatment in patients with acromegaly who will not benefit from or are not suitable for first-line neurosurgical treatment. Pharmacological treatments include somatostatin receptor ligands (such as octreotide, lanreotide and pasireotide), dopamine agonists and the growth hormone receptor antagonist pegvisomant. In this Primer, we review the main aspects of acromegaly, including scientific advances that underlie expanding knowledge of disease pathogenesis, improvements in disease management and new medical therapies that are available and in development to improve disease control.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Silent somatotroph pituitary adenomas: an update

Silent growth hormone adenomas (SGHA) are a rare entity of non-functioning pituitary neuroendocrine tumors. Diagnosis is invariably made post-operatively of a tumor immunopositive for GH (and Pit-1 in selected cases) but without clinical acromegaly. Mainly young females are affected, and tumors are often uncovered by investigation for headaches or oligoamenorrhea. Integration of clinical, pathological and biochemical data is required for proper diagnosis. Beside normal IGF-1 levels, a third of SGHAs displays elevated GH levels and some will eventually progress to acromegaly. Almost two-thirds will be mixed GH-prolactin tumors and sparsely-granulated monohormonal GH tumors seems the more aggressive subtype. Recurrence and need for radiation is higher than other non-functioning tumors so close follow-up is warranted.

Age- and Sex-Specific Differences as Predictors of Surgical Remission Among Patients With Acromegaly

CONTEXT

Sex and age are factors conferring resistance to medical treatment in patients with acromegaly. However, their impact on outcomes of transsphenoidal-selective adenomectomy (TSA) has not been evaluated.

OBJECTIVE

To analyze age- and sex-related differences concerning surgical outcomes of growth hormone (GH)-secreting pituitary adenomas.

DESIGN

Retrospective.

SETTING

Single-center tertiary hospital.

PARTICIPANTS

Patients with acromegaly (n = 463) who underwent TSA between January 2000 and July 2014.

INTERVENTION

TSA.

MAIN OUTCOME MEASUREMENTS

Tumor characteristics and surgical outcomes.

RESULTS

Sex differences existed in the baseline insulinlike growth factor-1 levels and the mean tumor size. Overall, surgical remission rates were 89.7% and 76.5% in male and female patients, respectively (P < 0.001). Total tumor tissue resection was performed in 92.6% and 85.8% of male and female participants, respectively (P = 0.021). Premenopausal women had a higher proportion of pituitary adenoma with cavernous sinus invasion than did men aged <50 years (35.3% vs 21.7%, P = 0.007). In immediate postoperative, 75-g oral glucose tolerance tests, fewer premenopausal women reached <1 ng/dL nadir GH levels than did men aged <50 years (59.9% vs 87.7%, P < 0.001). Surgical results were similar in both sexes among older patients (≥50 years). However, premenopausal women had significantly lower long-term remission rates than did men aged <50 years (69.3% vs 88.0%, P < 0.001).

CONCLUSION

Premenopausal women with acromegaly tend to have larger tumors, more aggressive tumor types, and lower remission rates than do men. However, further studies on the clinical implications are needed.

Clinical profile of silent growth hormone pituitary adenomas; higher recurrence rate compared to silent gonadotroph pituitary tumors, a large single center experience

PURPOSE

Study and comparison of characteristics of silent growth hormone adenomas (SGHA), silent corticotroph adenomas (SCA), and silent gonadotroph adenomas (SGA) in a single institution cohort of surgically treated pituitary adenomas.

METHODS

Retrospective analysis of SGHA surgically resected over 10 years: SGHA was defined as no clinical or biochemical evidence of acromegaly and positive GH immunostaining.

RESULTS

Of 814 pituitary surgeries; 2.1% (n = 17) were SGHA, 4.5% (n = 37) SCA, and 18.9% (n = 70/371; 2011-2016) SGA. Mean age at SGHA diagnosis was 43 years, with a large female predominance (82%). Mean tumor size and cavernous/sphenoid sinus invasiveness for SGHA, SCA, and SGA were 1.5 ± 1.0 cm and 25%, 2.5 ± 1.2 cm and 43%, 2.9 ± 2.0 cm and 41%, respectively (tumor size p = 0.009, SGHA vs. SGA, and invasion p; not-significant). During mean follow-up of 3.9 years, two patients (11%) developed elevated insulin-like growth factor-1 and five patients (29%) required a second surgery for tumor recurrence. Rate of surgical reintervention was similar to SCA (31%), but higher than SGA (10%) (p = 0.035, SGHA vs. SGA), and 18% underwent radiation therapy, similar to SCA (19%, p; not-significant) but higher than SGA (2.9%, p = 0.018).

CONCLUSION

This is the largest single center study characterizing SGHA behavior with SGA and SCA control groups in a cohort of surgically resected pituitary adenomas. SGHA present mostly in young females, and should be closely followed due to their higher likelihood of recurrence and potential of progression to clinical acromegaly. We propose that a complete hormonal staining panel be routinely performed for all pituitary adenomas.