Piperidine renin inhibitors: from leads to drug candidates.

Non-peptidomimetic renin inhibitors of the piperidine type represent a novel structural class of compounds potentially free of the drawbacks seen with peptidomimetic compounds so far. Synthetic optimization in two structural series focusing on improvement of potency, as well as on physicochemical properties and metabolic stability, has led to the identification of two candidate compounds 14 and 23. Both display potent and long-lasting blood pressure lowering effects in conscious sodium-depleted marmoset monkeys and double transgenic rats harboring both the human angiotensinogen and the human renin genes. In addition, 14 normalizes albuminuria and kidney tissue damage in these rats when given over a period of 4 weeks. These data suggest that treatment of chronic renal failure patients with a renin inhibitor might result in a significant improvement of the disease status.

Substituted piperidines--highly potent renin inhibitors due to induced fit adaptation of the active site.

The identification, synthesis and activity of a novel class of piperidine renin inhibitors is presented. The most active compounds show activities in the picomolar range and are among the most potent renin inhibitors ever identified.

Piperidine-renin inhibitors compounds with improved physicochemical properties.

Piperidine renin inhibitors with heterocyclic core modifications or hydrophilic attachments show improved physical properties (lower lipophilicity, improved solubility). Tetrahydroquinoline derivative rac-30 with a molecular weight of 517 and a log D(pH 7.4) of 1.9 displays potent and long lasting blood pressure lowering effects after oral administration to sodium depleted conscious marmosets.

Renin inhibition by substituted piperidines: a novel paradigm for the inhibition of monomeric aspartic proteinases?

BACKGROUND: The aspartic proteinase renin catalyses the first and rate-limiting step in the conversion of angiotensinogen to the hormone angiotensin II, and therefore plays an important physiological role in the regulation of blood pressure. Numerous potent peptidomimetic inhibitors of this important drug target have been developed, but none of these compounds have progressed past clinical phase II trials. Limited oral bioavailability or excessive production costs have prevented these inhibitors from becoming new antihypertensive drugs. We were interested in developing new nonpeptidomimetic renin inhibitors. RESULTS: High-throughput screening of the Roche compound library identified a simple 3, 4-disubstituted piperidine lead compound. We determined the crystal structures of recombinant human renin complexed with two representatives of this new class. Binding of these substituted piperidine derivatives is accompanied by major induced-fit adaptations around the enzyme's active site. CONCLUSIONS: The efficient optimisation of the piperidine inhibitors was facilitated by structural analysis of the renin active site in two renin-inhibitor complexes (some of the piperidine derivatives have picomolar affinities for renin). These structural changes provide the basis for a novel paradigm for inhibition of monomeric aspartic proteinases.

Identification of the active-site serine in human pancreatic lipase by chemical modification with tetrahydrolipstatin.

A chemical modification approach was used in this study to identify the active site serine residue of human pancreatic lipase. Purified human pancreatic lipase was covalently modified by incubation with [3H], [14C] tetrahydrolipstatin (THL), a potent inhibitor of pancreatic lipase. The radiolabeled lipase was digested with thermolysin, and the peptides were separated by HPLC. A single THL-peptide-adduct was obtained which was identical to that obtained earlier from porcine pancreatic lipase. This pentapeptide with the sequence VIGHS is covalently bound to a THL molecule via the side chain hydroxyl group of the serine unit corresponding to Ser-152 of the lipase. The selective cleavage of the THL-serine bond by mild acid treatment resulted in the formation of the delta-lactone Ro 40-4441 in high yield and clearly proves that THL is attached via an ester bond and with retention of stereochemistry at all chiral centers to the side chain hydroxyl group of Ser-152 of the lipase. The results obtained for human pancreatic lipase corroborate the inhibition mechanism of THL found on the porcine enzyme, and are in full agreement with the identification of the Ser-152 ... His-263 ... Asp-176 catalytic triad in the X-ray structure of human pancreatic lipase.

In vitro pharmacological properties of a series of isoprenaline derivatives.

The p-trifluoromethylanilide congener of isoprenaline, tert-butyl N-[(S)[( 4-[(R)-6-[2-(3,4-dihydroxyphenyl-2- hydroxyethyl]amino]heptanamido]phenyl]methyl][(N-methylcarbamoy l) methyl]carbamoyl]methyl]carbamate (1S,4R)-4,7,7-trimethyl-3-oxo-2- oxabicyclo[2.2.1]heptane-1-carboxylate (1:1) (Ro 17-2218) was investigated for its effects in various pharmacological tests in vitro and compared to the parent compound. As Ro 17-2218 represented a mixture of four diastereomers, the pure isomers were synthesized. They had a purity of 97-98%. By pharmacological testing of the diastereomers the highest potency was found in the 6R,2'R-isomer Ro 17-8648, while the potency of the 6S,2'S-isomer, Ro 17-9651 was lower by three orders of magnitude. The amorphous hydrochloride Ro 17-8648/001 had 1/10 the potency of the respective crystalline camphanate Ro 17-8648/003. (R)-6-[(R)-[2-(3,4-Dihydroxyphenyl)-2-hydroxyethyl]amino]-N-[4- (trifluoromethyl) phenyl]heptan amide (Ro 17-8648/003) was found to have potent beta-agonist properties with clear beta 1-selectivity in radioligand binding studies. It exerted an extremely tight binding to membrane receptors. As a full beta-agonist it elicited positive inotropic effects in isolated cardiac tissues, with a potency 10-360 times that of isoprenaline and an extremely long duration of action. Electrophysiological studies in isolated guinea-pig papillary muscles confirmed the beta 1-receptor-mediated effects of the compound.

[Androgen binding in human plasma and its physiological significance (author's transl)]. / Die Androgenbindung im menschlichen Plasma und ihre physiologische Bedeutung

The literature on the determination and the meaning of androgen binding to plasma proteins is reviewed. Because of the high affinity for the active androgens the sex hormone binding globulin (SHBG) is of considerable importance. The blood level of this globulin varies according to sex, age, medicamentation and pathological conditions. The influence of protein binding on the metabolism and mechanism of action of androgens is discussed and the hypotheses of several authors are compared.

[Study of Brazilian agricultural workers. A medico-socio-psychological study]. / Untersuchung von Landarbeitern in Brasilien Eine medizinisch-sozialpsychologische Studie

UNLABELLED: The general state of health of native Brazilian agricultural workers - a total of 750 people from 3 different plantations in the States of Paraná and Saso Paulo - was examined. The main interest of this study war centred on infectious and parasitic diseases, nutritional conditions as well as social, intellectual factors. OBSERVATIONS: Apart from the high number of cases of helminthiasis, amounting to 80%, the general state of health of the examined subjects was found to be good - indeed better than that of a hypothetical, comparable group of Europeans. Except for the Chagas' disease, by which 5% of the test subjects were afflicted, infectious diseases posed no serious problems. There was no case of malnutrition. The relatively lower intellectual level can not be attributed to any heriditary factor, and could definitely be improved by proper schooling. Corrective measures: Chagas: Since brick houses have replaced the wooden ones for several years, new infections are unlikely. Helminthiasis: In addition to the anthelminthic treatment, sanitary prophylactic measures should be taken. Social-intellectual factors: The following points should be emphasized: elementary schooling on the plantations; teaching at intermediary level; sewing and cooking courses; general hygience.