Óxido nítrico: un campo abierto para la angiología y la cirugía vascular / Nitric oxide: open field to angiology and vascular surgery

Objetivo. El objetivo es promover la formación continua de los profesionales de la cirugía vascular y angiología mediante una recopilación de las últimas publicaciones sobre el tema. Desarrollo. Abordamos la bioquímica, formación, regulación, acciones, posibles usos y la relevancia clínica de la molécula de óxido nítrico, compuesto sintetizado por la mayoría de las células de los mamíferos y que presenta efectos vasomotores locales y sistémicos de importancia para la mayoría de las patologías y tratamientos del ámbito de la cirugía vascular y de la angiología. Conclusión. Se han identificado las diversas áreas de actuación para su uso y se ha sugerido la terapia manipuladora de la respuesta endógena del compuesto mencionado, con el fin de obtener mejores resultados en los ámbitos de la medicina citados anteriormente (AU)

Synthesis of human renin inhibitory peptides, angiotensinogen transition-state analogs containing a retro-inverso amide bond.

The experimental details for the synthesis of human renin inhibitors are described. In order to avoid metabolic degradation of the Phe-His (P3-P2) amide bond in transition-state analogs, structurally modified acyl residues (P4-P3) were incorporated into the inhibitors. Compound 1a, which contained 2-(1-naphthylmethyl)-3-(N-phenethylcarbamoyl)propionyl residue (P4-P3) with a retro-inverso amide bond, L-histidine, and norstatine isoamylamide residue (P1-P1) as a transition-state mimic, had potent human renin inhibitory activity, and it lowered blood pressure when administered orally to common marmosets.

Renin inhibitors containing psi[CH2O] pseudopeptide inserts.

Renin inhibitors 2-4 with the D-Lys renin inhibitory peptide (RIP) sequence, but containing Leu psi[CH2O]Ala (2), Leu psi[CH2O]Val (3), and Leu psi[CH2O]Leu (4) at the P1-P1' site, were of a comparable potency to RIP. N-Terminal Boc-protected inhibitors containing Pro psi[CH2O]Phe in positions P4-P3 were potent inhibitors of renin, with Boc-Phe-Pro psi[CH2O]Phe-His-Leu psi[CH(OH)CH2]Val-Ile-(2-aminomethyl) pyridine (17) having an IC50 of 1.6 X 10(-9) M.

Renin inhibitors. Design and synthesis of a new class of conformationally restricted analogues of angiotensinogen.

Molecular modeling methods have been used to design a novel series of conformationally constrained cyclic peptide inhibitors of human renin. Three goals were defined: enhanced inhibitory potency, high specificity for renin, and increased metabolic stability. Three cyclic compounds were synthesized with ring sizes 10, 12, and 14, based upon a linear hexapeptide inhibitor with a reduced amide replacing the scissile bond at the active site. When tested, the 14-membered-ring compound was as potent an inhibitor of human renin as the parent while the 12-membered-ring compound was 6-fold more potent than the parent against mouse renin. However, the 10-membered-ring compound was inactive against both renins. The lack of potency of the 10-membered compound was explained by using NMR and molecular modeling techniques. It forms another conformation in solution that is inconsistent with binding at the active site. The cyclic compounds did not inhibit either pepsin or cathepsin D significantly. The cyclic modification rendered these inhibitors significantly resistant to cleavage by chymotrypsin and thus prevented loss of activity by this enzyme. Thus, the goals of enhanced inhibitory potency, high specificity, and metabolic stability were achieved in the series of compounds.

Design, structure-activity, and molecular modeling studies of potent renin inhibitory peptides having N-terminal Nin-For-Trp (Ftr): angiotensinogen congeners modified by P1-P1' Phe-Phe, Sta, Leu psi[CH(OH)CH2]Val or leu psi[CH2NH]Val substitutions.

A structure-conformation-activity investigation of several angiotensinogen (ANG) based inhibitors of human renin modified by either Phe-Phe, Sta, Leu psi[CH2NH]Val, or Leu psi[CH(OH)CH2]Val at the P1-P1' clevage site and P5 Trp(Nin-For) (Ftr) was performed. Specifically, Ac-Ftr-Pro-Phe-His-Phe-Phe-Val-Ftr-NH2 (1) provided a potent (KI = 2.7 X 10(-8) M) P1-P1' Phe-Phe substituted renin inhibitor to initiate these studies. Substitution of the P1-P1' Phe-Phe in compound 1 by Sta effected a 1,000-fold increase in biological potency for the resultant octapeptide Ac-Ftr-Pro-Phe-His-Sta-Val-Ftr-NH2 (10; KI = 6.7 X 10(-11) M). Kinetic analysis of compound 10 showed it to be a competitive inhibitor of human renin catalyzed proteolysis of human ANG. Chemical modifications of the compounds 1 and 10 were evaluated on the basis of comparative human plasma renin inhibitory activities (IC50 values) in vitro. Carboxy-terminal truncation studies on compound 10 showed that the P2' Val and P3' Ftr residues could both be eliminated without significant loss (ca. 10-fold) in renin inhibitory activity as exemplified by the pentapeptide Ac-Ftr-Pro-Phe-His-Sta-NH2 (12; IC50 = 3.8 X 10(-9) M). In addition, the corresponding P1-P1' Leu psi[CH(OH)CH2]Val and Leu psi[CH2NH]Val derivatives of compound 12 were potent renin inhibitors: Ac-Ftr-Pro-Phe-His-Leu psi[CH(OH)CH2]Val-NH2 (13; IC50 = 3.1 X 10(-10) M) and Ac-Ftr-Pro-Phe-His-Leu psi[CH2NH]Val-NH2 (14; IC50 = 2.1 X 10(-8) M). The structure-conformation-activity properties of the N-terminal Ftr substitution of these human renin inhibitors was examined by (1) comparative analysis of several analogues of 1 and Ac-Ftr-Pro-Phe-His-Sta-Ile-NH2 (17; IC50 = 1.0 X 10(-10) M) having P5 site modifications by Trp, His, D-Ftr, and D-His, (2) deletion of the N-terminal Ftr residue from compounds 12 and 17, to provide Ac-Pro-Phe-His-Sta-Ile-NH2 (16; IC50 = 3.1 X 10(-8) M) and Ac-Pro-Phe-His-Sta-NH2 (15; IC50 = 5.6 X 10(-6) M), and (3) computer modeling and dynamics studies of compounds 1 and 17 bound to CKH-RENIN, a simulated human renin model, which were focused on identifying potential intermolecular interactions of their common P5-P2 sequence, Ac-Ftr-Pro-Phe-His, at the enzyme active site.(ABSTRACT TRUNCATED AT 400 WORDS)