[Direct renin inhibitor aliskiren in the treatment of cardiovascular and renal diseases]. / Prímý inhibitor reninu aliskiren v lécbe kardiovaskulárních a renálních onemocnení.

The role of renin-angiotensin-aldosterone system (RAAS) in regulating the volume and composition of extracellular fluid, blood pressure (BP) as well as onset and progression of cardiovascular and renal diseases has been studied for more than 150 years. The compounds that block the vital stages of the RAAS cascade, such as ACE-inhibitors (ACEI), AT1-receptor blockers (ARB) and aldosterone receptor antagonists, importantly extended our treatment options. However, the positive therapeutic effects of these compounds also have certain negative consequences. Administration of ACEIs and ARBs interrupts physiological feedback for renal renin release and leads to reactive elevation of circulating active renin and greater production of angiotensin I and angiotensin II with subsequent return of aldosterone secretion to the pre-treatment levels ('escape' phenomenon). These possible adverse effects of the intermediary products of incomplete RAAS blockade leading to organ complications have facilitated the efforts to develop compounds blocking the initial stages of renin-angiotensin cascade--i.e. direct renin blockers. After several years of unsuccessful attempts, the recent years have seen development of the first non-peptide, orally long-term effective renin inhibitor, aliskiren fumarate. In monotherapy or in combination with other antihypertensives (hydrochlorothiazide, ARB, ACEI), aliskiren reduces BP in a dose-dependent manner (75-600 mg/den). Aliskiren reduces plasma renin activity (PRA) and neutralises hydrochlorothiazide-induced RAAS activation. Once daily administration of the drug leads to longer than 24-hour activity and its prolonged blocking effects on the kidneys are the basis for its renoprotectivity. In addition to the significant antihypertensive effect, clinical studies also showed a range of organoprotective properties in patients with left ventricle hypertrophy (ALLAY study), heart failure (ALOFT study) and diabetic nephropathy (AVOID study). Similar to other AT1-blockers, aliskiren has a minimum of adverse side effects. Aliskiren for hypertension therapy was launched in clinical practice in USA in 2007 (Tekturna and combination formulation TekturnaHCl, respectively) and shortly after that in European Union as Rasilez. In the Czech Republic, aliskiren (Rasilez) was released for clinical use by diabetologists and nephrologists in patients with hypertension and concomitant diabetes, nephropathy and proteinuria in doses of 150-300 mg per day on 1. 8. 2009. It is recommended as monotherapy or in combination with other antihypertensives to treat conditions with elevated PRA, including PRA elevation following diuretic, ACEI or ARB administration. Aliskiren might be used in patients who do not tolerate ACEIs as well as in patients in whom angiotensin II participates in the pathogenesis of their diseases. Reno-protective properties leading to a reduction in proteinuria and delaying renal failure progression were observed in patients with diabetic as well as non-diabetic nephropathy. The drug is the subject to similar precautions and contraindications as ACEIs and ARBs, i.e. pregnancy and bilateral renal artery stenosis. To make meaningful conclusions about the so far positive contribution of this new treatment class and its broad applicability for the therapy of hypertension and other cardiovascular diseases, it will be imperative to assess its long-term effects on morbidity and mortality as well as to compare these agents with other RAAS blockers in long-term clinical studies; this represents a research effort for another 7-8 years.

Antonín vancura and arterial hypertension. 50 years' evolution in the conception of pathogenesis and treatment of the disease.

A historical overview of the important contributions of Prof. Antonin Vancura from Charles University Medical Faculty, Prague, to the broader understanding of the pathogenesis, clinical course and classification of arterial hypertension is given in his pivotal publication and first Czech monography 'High Blood Pressure'. His unique clinical series of 1,096 hypertensive patients with their long-term follow-up after 5, 10 and 15 years made it possible to work out the classification of hypertension not only on the basis of blood pressure readings, but also according to target organ damage--a principle which is close to the 2003 classification of the European Society of Hypertension/European Society of Cardiology (ESH/ESC). In agreement with today's conception, Vancura emphasized already in 1942 the importance of metabolic changes and albuminuria for prognosis of the disease. In spite of the technical, instrumental and laboratory limitations, it is possible to gain from Vancura's publication a modern interpretation of his results given by a long-term follow-up of this large group of patients. In many ways, Vancura outstripped his time and his concepts approached today's standings and so founded one of the important schools of hypertension in Czechoslovakia and Europe.

Association of -344/T/C aldosterone synthase polymorphism (CYP11B2) with left ventricular structure and humoral parameters in young normotensive men.

BACKGROUND: Aldosterone plays an important role in development of left ventricular (LV) hypertrophy and myocardial fibrosis. We assessed the influence of the T-344C polymorphism of aldosterone synthase - the rate-limiting enzyme in aldosterone biosynthesis - on the structure of the left ventricle in young normotensive men. DESIGN AND METHODS: The population included 113 normotensive mid-European Caucasian men aged 18-40 years (mean 27 +/- 5 years). The genotype was assessed using polymerase chain reaction with subsequent cleavage with restriction enzyme HAEIII (restriction fragment length polymorphism method) and visualization with ethidium bromide. Plasma renin activity (PRA) and plasma aldosterone were measured. All subjects were examined by echocardiography and LV mass was assessed by using M-mode based ASE formula. RESULTS: The distribution of the genotypes was TT 23%:TC 55%:CC 22%. There were no differences in blood pressure among the groups. Men with the TT genotype had significantly higher levels of PRA (2.7 +/- 1.7 vs 1.8 +/- 1.0 vs 1.8 +/- 1.1 ng/ml/h, p < 0.01) and slightly higher plasma levels of aldosterone (113 +/- 64 vs 93 +/- 43 vs 87 +/- 39 pg/ml, p = 0,12). In the whole population, LV mass index (LVMI) did not differ significantly among the genotypes (92 +/- 16 vs 86 +/- 18 vs 84 +/- 16 g/m, p=0.20). In the population divided according to PRA, subjects with high renin had significantly higher LVMI in presence of the TT genotype (95 +/- 17 vs 84 +/- 16 vs 81 +/- 15 g/m, p < 0.05). CONCLUSIONS: In agreement with previous studies, we found that the TT genotype of T-344C polymorphism of aldosterone synthase gene was associated with significantly higher levels of PRA in normotensive men. In subjects with high PRA, the TT genotype was associated with higher values of the LVMI.

Association between tyrosine hydroxylase polymorphisms and left ventricular structure in young normotensive men.

Tyrosine hydroxylase (TH) is a rate-limiting enzyme for catecholamine biosynthesis. Increased sympathetic activity is associated with an increased left ventricular (LV) mass. However, the influence of TH gene polymorphisms on LV structure and function has yet to be investigated. Here, we analyse the association of Val-81-Met and tetranucleotide TCAT repeat TH polymorphisms with LV structure and function (assessed by echocardiography) in 108 normotensive men aged < or = 35 years (mean age: 25+/-4 years) with body mass index (BMI) < or = 30 kg/m2 (mean BMI: 23+/-3 kg/m2). The distribution of genotypes was VV homozygotes (n=42), VM heterozygotes (n=49) and MM homozygotes (n=17). The Val-81-Met polymorphism showed significant linkage disequilibrium with the TCAT polymorphism (P<0.0001). No differences were seen between the subgroups with respect to age, BMI and blood pressure. Compared with the VV and VM genotypes, subjects with the MM genotype showed significantly (all P<0.05) increased LV cavity diameter (VV: 52.8+/-3.9 mm, VM: 52.9+/-3.6 mm, MM: 56.1+/-3.2 mm), global LV mass (VV: 159+/-31 g, VM: 165+/-36 g, MM: 187+/-30 g) and LV mass index (VV: 81+/-14 g/m2, VM: 84+/-17 g/m2, MM: 93+/-12 g/m2). No differences were seen between the subgroups in parameters of LV function. In addition, plasma epinephrine and norepinephrine levels were comparable in the three subgroups. The results suggest an important association between the MM genotype of Val-81-Met TH gene polymorphism and increased LV cavity dimension and mass in a young normotensive male population, indicating an important role for genetic determination of the sympathetic system in LV growth.

Genetic analysis of metabolic defects in the spontaneously hypertensive rat.

Abnormalities in carbohydrate and lipid metabolism are common in patients with essential hypertension and in the spontaneously hypertensive rat (SHR). To identify chromosome regions contributing to this clustering of cardiovascular risk factors in the SHR, we searched for quantitative trait loci (QTL) associated with insulin resistance, glucose intolerance, and dyslipidemia by using the HXB/BXH recombinant inbred (RI) strains. Analysis of variance in RI strains suggested significant effects of genetic factors. A genome screening of the RI strains with more than 700 markers revealed QTL significantly associated with insulin resistance on Chromosomes (Chrs) 3 and 19. The Chr 19 QTL was confirmed by testing a previously derived SHR-19 congenic strain: transfer of a Chr 19 segment delineated by markers D19Rat57 and D19Mit7 from the Brown Norway (BN/Cr) strain onto the genetic background of the SHR/Ola was associated with decreased insulin and glucose concentrations and ameliorated insulin resistance at the tissue level. These findings suggest that closely linked genes on Chr 19, or perhaps even a single gene with pleiotropic effects, influence the clustering of metabolic disturbances in the SHR-BN model.