Acromegaly Is More Severe in Patients With AHR or AIP Gene Variants Living in Highly Polluted Areas

CONTEXT

An increased prevalence of acromegaly was found some years ago in a highly polluted area in North-Eastern Sicily, where high concentration of nonmethane hydrocarbons, volatile organic compounds, and cadmium was found. Aryl hydrocarbon receptor (AHR) pathway has a key role in detoxification of these compounds and in tumorigenesis.

OBJECTIVE

We correlated the occurrence of AHR and/or AHR-interacting protein (AIP) gene variants with acromegaly severity according to pollution exposition.

DESIGN, SETTING, AND PATIENTS

This was an observational, perspective study conducted over 7 years in four Italian referral centers for pituitary diseases in which 210 patients with acromegaly were enrolled between 2008 and 2015.

INTERVENTION

Genetic screening of patients for AHR and AIP variants.

MAIN OUTCOME MEASURES

Clinical, biochemical, and radiological data of patients with and without AIP and/or AHR gene variants, living in polluted (high-risk for health, [HR]) or nonpolluted (NP) areas of five Italian regions were evaluated and compared.

RESULTS

Among the 23 patients from HR areas, nine showed AHR or AIP variants. Mean IGF-I levels and pituitary tumor diameter were significantly higher in these nine patients (HR/VAR+) than in the other 14 (HR/VAR−) and in the 187 from NP areas (44 NP/VAR+). Somatostatin analogs significantly decreased mean GH and IGF-I levels in patients from NP areas and in HR/VAR− (GH P < .05; IGF-I times the upper limit of normal P < .01) but not in HR/VAR+ group.

CONCLUSIONS

Genetic variants potentially inducing functional abnormalities of the aryl hydrocarbon receptor (AHR) pathway are associated with a more severe acromegaly, increased pituitary tumor size, and somatostatin analog resistance in patients living in HR areas.

Somatostatin receptor expression in adrenocortical tumors and effect of a new somatostatin analog SOM230 on hormone secretion in vitro and in ex vivo adrenal cells

BACKGROUND

Somatostatin is a widely distributed polypeptide that modulates endocrine and exocrine secretion, cell proliferation, and apoptosis by 5 somatostatin receptors (SSTR1-5). The inhibitory effects of somatostatin on tumor growth may be the result of its suppressing the synthesis and/or secretion of growth factors and growth-promoting hormones.

AIM

Very little information is available on the effect of somatostatin analogs on adrenal tumors, so we examined SSTR expression in adrenocortical tumors and studied the effect of a somatostatin analog (SOM230) on hormone secretion and cell viability in adrenal cells.

MATERIAL/SUBJECTS AND METHODS

SSTR expression was analyzed by real-time PCR in 13 adrenocortical carcinomas (ACC), 24 aldosterone-producing adenomas (APA), 11 cortisol-producing adenomas (CPA), and 7 normal adrenals (NA), and verified by immunohistochemistry (IHC) in 14 samples. The effect of SOM230 on cortisol or aldosterone secretion in H295R and primary cell cultures was determined by radioimmunoassay, and its effect on viability in H295R and SW13 using the MTT test.

RESULTS

SSTR1 and SSTR2 mRNA was expressed in 100% of adrenal tumors. Compared to NA, ACC revealed an increase in almost all SSTR, while only some APA over-expressed SSTR3 and SSTR1. CPA expressed SSTR similar to NA. IHC confirmed the mRNA expression data. At nanomolar concentrations, SOM230 inhibited hormone secretion in primary adrenal cultures and H295R cells, but had no evident effect on cell viability.

CONCLUSIONS

The evidence of SSTR over-expression (particularly in ACC) and of hormone secretion being inhibited by SOM230 suggests a potential therapeutic role for this broad-spectrum somatostatin analog in adrenal tumors.

A case of primary aldosteronism in pregnancy: do LH and GNRH receptors have a potential role in regulating aldosterone secretion?

OBJECTIVE

The mechanisms inducing steroidogenesis in primary aldosteronism (PA) remain poorly defined. It was recently demonstrated that some G-protein-coupled receptors are abnormally expressed in aldosterone-producing adenomas (APA). We evaluated the potential role of LH and GNRH receptors (LHR (or LHCGR) and GNRHR) in regulating aldosterone secretion in a patient with APA arising during pregnancy (index case) and in a subset of other patients with PA.

PATIENTS AND METHODS

GNRH test was performed in the index case, 11 other PA, and 5 controls. GNRHR and LHR expressions were examined in 23 APA and 6 normal tissues.

RESULTS

Aldosterone response increased significantly (114%) in the index case after GNRH test was performed preoperatively, while it was blunted after adrenalectomy. Aldosterone also increased after human chorionic gonadotropin and triptorelin stimulation. A partial aldosterone response to GNRH was observed in other 7/11 PA, while a significant response was observed in two patients. Controls did not respond to GNRH test. GNRHR was overexpressed and LHR expression was moderate in the APA tissue from the index case. Moreover, LHR was found in normal adrenals and overexpressed in 6/22 APA. GNRHR was overexpressed in 6/22 APA, 2 of them with a 95- and 109-fold higher expression than normal. A correlation between the clinical and molecular findings was observed in five out of seven patients.

CONCLUSION

We describe a case of PA diagnosed during pregnancy, which appeared to correlate with aberrant LHR and GNRHR expression. Our findings suggest that a subset of patients with PA has aberrant LHR and GNRHR expression, which could modulate aldosterone secretion.

Effect of canrenone and amiloride on the prooxidative effect induced by aldosterone in human mononuclear leukocytes in vitro

Clinical studies have demonstrated that aldosterone receptor antagonists do improve the survival of patients with chronic heart diseases and in vitro studies have shown that canrenone blocks the proinflammatory effect of aldosterone in mononucler leukocytes (MNL). The aim of the study was to compare, in the model of human MNL, the effect of potassium-sparing diuretics amiloride and canrenone, on the protein expression of p22phox, a NADPH-oxidase system subunit, that is a principal marker of production of superoxide anions. MNL were isolated from 10 informed healthy volunteers (5 males and 5 females, age range 24-36 yr) and the proteins extracted. p22phox protein expression was evaluated by Western blot and quantified using a densitometric semiquantitative analysis. The experiments showed that aldosterone (10(-8) M) enhances the protein expression of p22phox and that its effect is reversed by co-incubation with canrenone (10(-6) M), while incubation with amiloride (10(-6) M) reduced the prooxidative effect of aldosterone at a significantly lower extent than canrenone. Co-incubation with canrenone, amiloride, and aldosterone together produced the same effect as aldosterone plus canrenone. Incubation with cortisol (40(-8) M) was not effective. These data confirm the prooxidative effect of aldosterone in MNL. The addition of aldosterone-receptor antagonist canrenone produced a higher inhibition than sodium channel blocker amiloride on the effect of aldosterone on p22phox protein expression.

Cardiovascular risk factors and ultrasound evaluation of intima-media thickness at common carotids, carotid bulbs, and femoral and abdominal aorta arteries in patients with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency

CONTEXT

In congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, a tendency for obesity, high insulin, and high 24-h blood pressure levels has been reported in children and adolescents. Increased intima-media thickness (IMT) is considered a measure of subclinical atherosclerosis and a predictor of myocardial infarction and stroke.

OBJECTIVE

The objective of the study was to evaluate glucose metabolism, lipid profile, IMT of the abdominal aorta, right and left common carotids, carotid bulbs, and common femoral arteries in adult CAH patients.

SUBJECTS

Nineteen (10 females, nine males; 28 +/- 3.5 yr) patients (12 salt wasting and seven simple virilizing) and 19 (10 females, nine males) healthy subjects matched for anthropometric parameters (age, sex, body mass index, smoking habit, waist to hip ratio, and blood pressure).

METHODS

Glucose metabolism was studied using the oral glucose tolerance test and the homeostasis model assessment-insulin resistance. The echo-Doppler was used for arterial ultrasound. 17-Hydroxyprogesterone, androstenedione, testosterone, ACTH, plasma renin activity, total and high-density lipoprotein cholesterol, and triglycerides were measured.

RESULTS

CAH patients had significantly higher fasting plasma insulin (11.6 +/- 6.20 microU/ml vs 5.18 +/- 2.4 microU/ml; P < 0.0001) and homeostasis model assessment-insulin resistance than controls (2.46 +/- 1.92 vs 1.12 +/- 0.58; P = 0.0033). IMT of the studied arteries was higher in CAH patients than controls. There was no correlation between IMT and cumulative glucocorticoid doses and androgen levels.

CONCLUSION

A reduced insulin sensitivity and increased IMT were demonstrated in adults with CAH, who consequently need a follow-up for cardiovascular risk.

Idiopathic primary hyperaldosteronism: normalization of plasma aldosterone after one month withdrawal of long-term therapy with aldosterone-receptor antagonist potassium canrenoate

We have re-evaluated 15 patients with idiopathic primary aldosteronism one month after withdrawal of therapy with aldosterone-receptor antagonist potassium canrenoate. Therapy had lasted for 3 to 24 yr. Median blood pressure (BP) in the sitting position at the time of diagnosis was 160/100 (ranges 150-200/95-110 mmHg); while 1 month after withdrawal of therapy median BP was 145/90 (ranges 125-160/80-100 mmHg). One month after withdrawal, the ratio aldosterone (ng/dl)/plasma renin activity (ng/ml/h) in the upright position was increased only in 3 cases (median 18, range 6.1-125). We found a significant inverse correlation between the upright aldosterone/plasma renin activity (aldo/PRA) ratio, 1 month after withdrawal, and the number of years of therapy with potassium canrenoate. We conclude that long-term therapy with the aldosterone-receptor blocker, potassium canrenoate, can normalize the aldo/PRA ratio in many cases of idiopathic primary hyperaldosteronism after one-month withdrawal of the drug. These data are consistent with possible regression of idiopathic primary hyperaldosteronism after long-term therapy with potassium canrenoate, or in alternative to a persistent effect of potassium canrenoate, on aldosterone synthesis.

Spironolactone in the treatment of polycystic ovary syndrome: effects on clinical features, insulin sensitivity and lipid profile

This prospective clinical trial was designed to assess the effects of a long-term therapy with spironolactone, with and without dietary-induced weight-loss, on clinical features, lipid profile and insulin levels in women with polycystic ovary syndrome (PCOS). Twenty-five patients (range of age 16-32 yr; 13 lean and 12 overweight) fulfilling formal diagnostic criteria for PCOS (oligomenorrhea and/or amenorrhea, biochemical and/or clinical evidence of hyperadrogenism) were studied at baseline and then received oral spironolactone (100 mg/die) for 12 months; association with lifestyle modifications was recommended to all over-weight patients. Clinical, endocrine and metabolic parameters [oral glucose tolerance test (OGTT), lipid profile] were measured at baseline and at the end of the antiandrogen treatment. The therapy was associated with a significant average decline of triglycerides in overweight subjects and with increased HDL-cholesterol levels in lean patients. The insulin levels at 60 min during OGTT, homeostasis model assessment-insulin resistance and area under curve of insulin were significantly lowered in overweight women after 12 months of spironolactone and weight loss and no negative changes in insulin secretion and sensitivity were observed in PCOS women after pharmacological treatment alone. The efficacy of spironolactone on the androgenic clinical aspects of PCOS has been confirmed in this study. Furthermore, our data show that long-term treatment with spironolactone exerts no negative effects on lipoprotein profile and glucose metabolism; more relevant beneficial effects on glucose and lipid metabolism were observed when the antiandrogen was associated with weight loss in overweight PCOS women.

Licorice consumption and serum testosterone in healthy man

We have previously found that licorice can reduce serum testosterone in healthy men. These results were not confirmed in another study, where the same amounts of licorice did not decrease salivary testosterone values. In the actual study we treated more cases with the same amount of licorice and reproduced our previous data. The mean testosterone values decreased by 26 % after one week of treatment (p < 0.01). There was also a significant increase in 17-OHP and LH concentrations and a slight, but not significant decrease in free testosterone. Licorice treatment, in addition, did not affect the response of testosterone and 17-OHP to stimulation with beta-HCG.

Inactivating mutations of the mineralocorticoid receptor in Type I pseudohypoaldosteronism

Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Typical biochemical features include high levels of plasma aldosterone and renin, hyponatremia and hyperkalemia. Different mutations of the human mineralocorticoid receptor (hMR) gene have been identified in subjects affected by the autosomal dominant or sporadic form of the disease. Our laboratory has investigated a large number of subjects with familial and sporadic PHA1. Several different mutations have been detected, which are localized in different coding exons of the hMR gene. These mutations either create truncated proteins, either affect specific amino acids involved in receptor function. In this paper, we review hMR mutations described to date in PHA1 and their functional characterization. We discuss the absence of mutations in some kindreds and the role of precise phenotypic and biological examination of patients to allow for identification of other genes potentially involved in the disease.

Effect of licorice on the reduction of body fat mass in healthy subjects

The history of licorice, as a medicinal plant, is very old and has been used in many societies throughout the millennia. The active principle, glycyrrhetinic acid, is responsible for sodium retention and hypertension, which is the most common side-effect. We show an effect of licorice in reducing body fat mass. We studied 15 normal-weight subjects (7 males, age 22-26 yr, and 8 females, age 21-26 yr), who consumed for 2 months 3.5 g a day of a commercial preparation of licorice. Body fat mass (BFM, expressed as percentage of total body weight, by skinfold thickness and by bioelectrical impedance analysis, BIA) and extracellular water (ECW, percentage of total body water, by BIA) were measured. Body mass index (BMI) did not change. ECW increased (males: 41.8+/-2.0 before vs 47.0+/-2.3 after, p<0.001; females: 48.2+/-1.4 before vs 49.4+/-2.1 after, p<0.05). BFM was reduced by licorice: (male: before 12.0+/-2.1 vs after 10.8+/-2.9%, p<0.02; female: before 24.9+/-5.1 vs after 22.1+/-5.4, p<0.02); plasma renin activity (PRA) and aldosterone were suppressed. Licorice was able to reduce body fat mass and to suppress aldosterone, without any change in BMI. Since the subjects were consuming the same amount of calories during the study, we suggest that licorice can reduce fat by inhibiting 11beta-hydroxysteroid dehydrogenase Type 1 at the level of fat cells.