Prostatic disorders in acromegalic patients experience of a Brazilian center

Acromegaly and male sexual health

Acromegaly is a rare pathology characterized by chronic hypersecretion of Growth Hormone (GH) and Insulin-like Growth Factor-1 (IGF-1) that causes somatic, metabolic, and systemic changes. The somatotropic axis acts physiologically favoring gonadal function, but when GH is produced in excess it has deleterious effects on many aspects of male sexuality. It is widely demonstrated, in fact, that acromegaly induces hypogonadism through different mechanisms, both through direct mass effect on gonadotropic cells and through increased plasma levels of prolactin. Moreover, hypogonadism is also one of the factors linking acromegaly to erectile dysfunction (ED), but also metabolic complications of acromegaly and, probably, GH itself contribute to the genesis of this disorder. There are few data in the literature on the impact of the disease on fertility and testicular volume. Finally, knowledge of the role of GH hypersecretion on the occurrence of prostatic diseases such as benign prostatic hypertrophy and prostatic cancer appears to be of fundamental clinical importance in the long-term management of these patients.

Endocrinology of the Aging Prostate: Current Concepts

Benign prostate hyperplasia (BPH), one of the most common diseases in older men, adversely affects quality-of-life due to the presence of low urinary tract symptoms (LUTS). Numerous data support the presence of an association between BPH-related LUTS (BPH-LUTS) and metabolic syndrome (MetS). Whether hormonal changes occurring in MetS play a role in the pathogenesis of BPH-LUTS is a debated issue. Therefore, this article aimed to systematically review the impact of hormonal changes that occur during aging on the prostate, including the role of sex hormones, insulin-like growth factor 1, thyroid hormones, and insulin. The possible explanatory mechanisms of the association between BPH-LUTS and MetS are also discussed. In particular, the presence of a male polycystic ovarian syndrome (PCOS)-equivalent may represent a possible hypothesis to support this link. Male PCOS-equivalent has been defined as an endocrine syndrome with a metabolic background, which predisposes to the development of type II diabetes mellitus, cardiovascular diseases, prostate cancer, BPH and prostatitis in old age. Its early identification would help prevent the onset of these long-term complications.

The role of insulin-like growth factors in the development of prostate cancer

INTRODUCTION

Preclinical, clinical, and population studies have provided robust evidence for an important role for the insulin-like growth factor (IGF) system in the development of prostate cancer.

AREAS COVERED

An overview of the IGF system is provided. The evidence implicating the IGF system in the development of prostate cancer is summarized. The compelling evidence culminated in a number of clinical trials of agents targeting the system; the reasons for the failure of these trials are discussed.

EXPERT OPINION

Clinical trials of agents targeting the IGF system in prostate cancer were terminated due to limited objective clinical responses and are unlikely to be resumed unless a convincing predictive biomarker is identified that would enable the selection of likely responders. The aging population and increased screening will lead to greater diagnosis of prostate cancer. Although the vast majority will be indolent disease, the epidemics of obesity and diabetes will increase the proportion that progress to clinical disease. The increased population of worried men will result in more trials aimed to reduce the risk of disease progression; actual clinical endpoints will be challenging and the IGFs remain the best intermediate biomarkers to indicate a response that could alter the course of disease.

Obesity and metabolic dysfunction severely influence prostate cell function: role of insulin and IGF1

Obesity is a major health problem that courses with severe comorbidities and a drastic impairment of homeostasis and function of several organs, including the prostate gland (PG). The endocrine–metabolic regulatory axis comprising growth hormone (GH), insulin and IGF1, which is drastically altered under extreme metabolic conditions such as obesity, also plays relevant roles in the development, modulation and homeostasis of the PG. However, its implication in the pathophysiological interplay between obesity and prostate function is still to be elucidated. To explore this association, we used a high fat–diet obese mouse model, as well as in vitro primary cultures of normal‐mouse PG cells and human prostate cancer cell lines. This approach revealed that most of the components of the GH/insulin/IGF1 regulatory axis are present in PGs, where their expression pattern is altered under obesity conditions and after an acute insulin treatment (e.g. Igfbp3), which might have some pathophysiological implications. Moreover, our results demonstrate, for the first time, that the PG becomes severely insulin resistant under diet‐induced obesity in mice. Finally, use of in vitro approaches served to confirm and expand the conception that insulin and IGF1 play a direct, relevant role in the control of normal and pathological PG cell function. Altogether, these results uncover a fine, germane crosstalk between the endocrine–metabolic status and the development and homeostasis of the PG, wherein key components of the GH, insulin and IGF1 axes could play a relevant pathophysiological role.

The biomarker sex hormone-binding globulin - from established applications to emerging trends in clinical medicine

Sex hormone-binding globulin (SHBG) is a serum glycoprotein exhibiting the unique feature of binding sex steroids with high affinity and specificity. Its serum levels are regulated not only by androgens and estrogens but also by thyroid hormones and other metabolic factors. Several disease conditions are accompanied by altered SHBG levels such as hyper- and hypoandrogenism, thyroid disorders, pituitary diseases, liver disorders, and breast as well as prostate cancer. Additionally, several drugs and alcohol consumption influence serum concentrations of SHBG. In some cases, altered SHBG levels are a specific result of the underlying pathology. In others, they merely constitute an epiphenomenon, which still might offer the possibility of using serum measurements of SHBG as surrogate marker. This review article portrays the different disorders associated with altered SHBG levels and discusses the usefulness of SHBG as disease biomarker from a clinicians as well as from an endocrinological researchers point of view.

Prostatic hyperplasia in acromegaly, a myth or reality: a case-control study

CONTEXT

Disorders of the prostate gland are more prevalent in patients with acromegaly. GH-insulin-like growth factor 1 (IGF1) axis plays an additive role in prostatic growth and development.

OBJECTIVE

To correlate the structural and histopathological changes of the prostate and prostatic symptoms with GH/IGF1 in patients with acromegaly.

DESIGN

Case-control study, from January 2012 to November 2013.

SETTING

Tertiary referral centre university hospital in Northern India.

PATIENTS

Fifty-three men with acromegaly and 50 healthy men matched for age and BMI.

MAIN OUTCOME MEASURES

International Prostate Symptom Score (IPSS), prostate-specific antigen (PSA) levels, dimensions of the prostate on trans-rectal ultrasonography, parameters on uroflowmetry, and immunopositivity with anti-IGF1 antibody in prostatic tissue biopsies.

RESULTS

Despite low serum testosterone levels (8.9 nmol/l vs 14.3 nmol/l, acromegaly vs control), patients with acromegaly had marginally higher IPSS, PSA levels, and grades of enlarged prostate and obstructive features on uroflowmetry compared with controls. Dimensions of the prostate on ultrasonography were also significantly higher in patients. These changes were present irrespective of age, current gonadal status, and disease activity. Evidence of prostatic hyperplasia on biopsy was seen in six of 14 patients (42.8%) who underwent prostatic biopsy while it was absent in the controls. Immunohistochemistry with anti-IGF1 antibody showed moderate positivity in all the 14 patients who underwent biopsy with benign prostatic hyperplasia, compared with mild positivity in 21% of controls. Similarly, 14 control patients with prostatic malignancies showed variable positivity, four patients had strong, two each had mild and moderate positivity, while six were negative.

CONCLUSIONS

In patients with acromegaly, there is a higher frequency of structural changes in the prostate, along with greater prostatic volume and obstructive features, compared with healthy controls, irrespective of age, gonadal status, and disease activity.