Effect of captopril on post-infarction remodelling visualized by light sheet microscopy and echocardiography.

Angiotensin converting enzyme inhibitors, among them captopril, improve survival following myocardial infarction (MI). The mechanisms of captopril action remain inadequately understood due to its diverse effects on multiple signalling pathways at different time periods following MI. Here we aimed to establish the role of captopril in late-stage post-MI remodelling. Left anterior descending artery (LAD) ligation or sham surgery was carried out in male C57BL/6J mice. Seven days post-surgery LAD ligated mice were allocated to daily vehicle or captopril treatment continued over four weeks. To provide comprehensive characterization of the changes in mouse heart following MI a 3D light sheet imaging method was established together with automated image analysis workflow. The combination of echocardiography and light sheet imaging enabled to assess cardiac function and the underlying morphological changes. We show that delayed captopril treatment does not affect infarct size but prevents left ventricle dilation and hypertrophy, resulting in improved ejection fraction. Quantification of lectin perfused blood vessels showed improved vascular density in the infarct border zone in captopril treated mice in comparison to vehicle dosed control mice. These results validate the applicability of combined echocardiographic and light sheet assessment of drug mode of action in preclinical cardiovascular research.

Discovery of Cathepsin S Inhibitor LY3000328 for the Treatment of Abdominal Aortic Aneurysm.

Cathepsin S (Cat S) plays an important role in many pathological conditions, including abdominal aortic aneurysm (AAA). Inhibition of Cat S may provide a new treatment for AAA. To date, several classes of Cat S inhibitors have been reported, many of which form covalent interactions with the active site Cys25. Herein, we report the discovery of a novel series of noncovalent inhibitors of Cat S through a medium-throughput focused cassette screen and the optimization of the resulting hits. Structure-based optimization efforts led to Cat S inhibitors such as 5 and 9 with greatly improved potency and drug disposition properties. This series of compounds binds to the S2 and S3 subsites without interacting with the active site Cys25. On the basis of in vitro potency, selectivity, and efficacy in a CaCl2-induced AAA in vivo model, 5 (LY3000328) was selected for clinical development.

Varespladib (A-002), a secretory phospholipase A2 inhibitor, reduces atherosclerosis and aneurysm formation in ApoE-/- mice.

The family of secretory phospholipase A2 (sPLA2) enzymes has been associated with inflammatory diseases and tissue injury including atherosclerosis. A-001 is a novel inhibitor of sPLA2 enzymes discovered by structure-based drug design, and A-002 is the orally bioavailable prodrug currently in clinical development. A-001 inhibited human and mouse sPLA2 group IIA, V, and X enzymes with IC50 values in the low nM range. A-002 (1 mg/kg) led to high serum levels of A-001 and inhibited PLA2 activity in transgenic mice overexpressing human sPLA2 group IIA in C57BL/6J background. In addition, the effects of A-002 on atherosclerosis in 2 ApoE mouse models were evaluated using en face analysis. (1) In a high-fat diet model, A-002 (30 and 90 mg/kg twice a day for 16 weeks) reduced aortic atherosclerosis by 50% (P < 0.05). Plasma total cholesterol was decreased (P < 0.05) by 1 month and remained lowered throughout the study. (2) In an accelerated atherosclerosis model, with angiotensin II-induced aortic lesions and aneurysms, A-002 (30 mg/kg twice a day) reduced aortic atherosclerosis by approximately 40% (P < 0.05) and attenuated aneurysm formation (P = 0.0096). Thus, A-002 was effective at significantly decreasing total cholesterol, atherogenesis, and aneurysm formation in these 2 ApoE mouse models.

C.I. Pigment red 266.

C.I. Pigment Red 266, or 4-[[4-(aminocarbonyl)phenyl]hydrazono]-N-(2-methoxyphenyl)-3-oxo-3,4-dihydronaphthalene-2-carboxamide, C(25)H(20)N(4)O(4), adopts the keto-hydrazone tautomeric form with significant intramolecular hydrogen bonding. The molecules pack to form layers involving an extensive network of intermolecular hydrogen bonds, in which the primary amide group plays a prominent role. The good technical performance of this pigment in application may be attributed principally to the pattern of intra- and intermolecular hydrogen bonding.

Heart failure and greater infarct expansion in middle-aged mice: a relevant model for postinfarction failure.

Young mice tolerate myocardial loss after coronary artery ligation (CAL) without congestive heart failure (CHF) signs or mortality. We predicted a CHF phenotype after CAL in aged mice. Left coronary artery ligation produced permanent myocardial infarcts (MI). Mortality was higher in male 14-mo-old C57BL/6N mice (Older mice) than in 2-mo-old mice (Young mice) (16 of 25 Older mice died vs. 0 of 10 Young mice, P < 0.02). After 8 wk, rales, weight loss, and lethargy preceded deaths. Captopril (50 mg x kg(-1) x day(-1)) increased Older mouse survival (6 of 22 died, P < 0.02). Captopril improved systolic function (peak aortic blood velocity) from 76 +/- 6% of baseline in untreated Older mice to 93 +/- 8% (P < 0.036). At 24 h, MI comprised 28 +/- 4% of the left ventricle in Young mice, surprisingly larger than that in Older mice (18 +/- 2%, P < 0.011). Endocardial area underlying the infarct scar was significantly larger in Older mice than in Young mice. Captopril did not reduce expansion but markedly reduced septal hypertrophy. Aging reduces compensatory ability in mice despite smaller acute infarcts. Less effective myocardial repair, greater infarct expansion, and septal hypertrophy are seen with aging. Aging is a more relevant murine model of post-MI heart failure in patients.