11β-hydroxystéroïde déshydrogénases. Avancées récentes

Development and structure-activity relationships of tanshinones as selective 11β-hydroxysteroid dehydrogenase 1 inhibitors

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1) represents a promising drug target for metabolic syndrome, including obesity and type 2 diabetes. Our initial screen of a collection of natural products from Danshen led to the identification of tanshinones as the potent and selective 11β-HSD1 inhibitors. To improve the druggability and explore the structure-activity relationships (SARs), more than 40 derivatives have been designed and synthesized using tanshinone IIA and cryptotanshinone as the starting materials. More than 10 derivatives exhibited potent in vitro 11β-HSD1 inhibitory activity and good selectivity over 11β-HSD2 across human and mouse species. Based on the biological results, SARs were further discussed, which was also partially rationalized by a molecular docking model of 1 bound to the 11β-HSD1. Remarkably, compounds 1, 17 and 30 significantly inhibited 11β-HSD1 in 3T3-L1 adipocyte and in livers of ob/ob mice, which merits further investigations as anti-diabetic agents. This study not only provides a series of novel selective 11β-HSD1 inhibitors with promising therapeutic potentials in metabolic syndromes, but also expands the boundaries of the chemical and biological spaces of tanshinones.

[Hypokalemia with pseudo-hyperaldosteronism: Is it Lidl® syndrome?]

INTRODUCTION

Intoxication induced by glycyrrhizin is a common cause of hypokalaemia by pseudo-hyperaldosteronism.

OBSERVATION

We hereby present the observation of a 68-year old patient hospitalised following a full hip-prosthesis operation after a deep hypokalaemia at 2.5mM was observed, with ECG signs (flat T waves and appearance of U waves). The kaliuresis was not adapted at 8,4mmol/mmol of creatininuria. We noted a history of axonal and demyelinising polyneuropathy, of psoriasis and chronic ethylism.The evolution after intravenous potassic supplementation and then per os was favourable leading to a normalisation of the blood and urinary potassic concentrations. The blood concentrations of renin and of aldosterone upon admission were lower than the detection threshold and the tests carried out 7 days later were normal with a plasmatic renin of 35.2 pg/mL and a plasmatic aldosterone of 74 pg/mL, therefore indicating a toxic cause. It is the interview of the patient that allowed for the diagnosis, identifying a daily, prolonged and important consumption (around 1L every 2-3 days for several years) of a pastis produced by supermarket brand Lidl®. The composition of the drink mentions 'liquorice infusion' without giving any more information as regards to the real concentration; it was later estimated at 170 mg/L by the distributor.

DISCUSSION

The consumption of glycyrrhizin is a well-known aetiology for pseudo-hyperaldosteronism. It is commonly mentioned amongst excessive consumers of liquorice or of non-alcoholic anise drinks. Drinks that are derived from original pastis contain varying levels of glycyrrhizin, which is used as a flavour enhancer and can become toxic in cases of prolonged and important consumption.

[The old man and the syrup]

Intoxication by glycyrrhizin is a rare cause of hypokalemia. We describe a patient with severe hypokalemia caused by long-term consumption of syrup containing liquorice. The physiopathological mechanism of the intoxication and the differential diagnosis are presented.

Aldosterone-producing adenoma and other surgically correctable forms of primary aldosteronism

Surgically correctable forms of primary aldosteronism are characterized by unilateral aldosterone hypersecretion and renin suppression, associated with varying degrees of hypertension and hypokalemia. Unilateral aldosterone hypersecretion is caused by an aldosterone-producing adenoma (also known as Conn's adenoma and aldosteronoma), primary unilateral adrenal hyperplasia and rare cases of aldosterone-producing adrenocortical carcinoma. In these forms, unilateral adrenalectomy can cure aldosterone excess and hypokalemia, but not necessarily hypertension. The prevalence of primary aldosteronism in the general population is not known. Its prevalence in referred hypertensive populations is estimated to be between 6 and 13%, of which 1.5 to 5% have an aldosterone-producing adenoma or primary unilateral adrenal hyperplasia. Taking into account referral biases, the prevalence of surgically correctable primary aldosteronism is probably less than 1.5% in the hypertensive population and less than 0.3% in the general adult population. Surgically correctable primary aldosteronism is sought in patients with hypokalemic, severe or resistant forms of hypertension. Recent recommendations suggest screening for primary aldosteronism using the aldosterone to renin ratio. Patients with a raised ratio then undergo confirmatory suppression tests. The differential diagnosis of hypokalemic hypertension with low renin includes mineralocorticoid excess, with the mineralocorticoid being cortisol or 11-deoxycorticosterone, apparent mineralocorticoid excess, pseudo-hypermineralocorticoidism in Liddle syndrome or exposure to glycyrrhizic acid. Once the diagnosis is confirmed, adrenal computed tomography is performed for all patients. If surgery is considered, taking into consideration the clinical context and the desire of the patient, adrenal vein sampling is performed to detect whether or not aldosterone hypersecretion is unilateral. Laparoscopic surgery for unilateral aldosterone hypersecretion is associated with a morbidity of about 8%, with most complications being minor. It generally results in the normalization of aldosterone secretion and kalemia, and in a large decrease in blood pressure, but normotension without treatment is only achieved in half of all cases. Normotension following adrenalectomy is more frequent in young patients with recent hypertension than in patients with long-standing hypertension or a family history of hypertension.