Important role of local angiotensin II activity mediated via type 1 receptor in the pathogenesis of cardiovascular inflammatory changes induced by chronic blockade of nitric oxide synthesis in rats

Anti-monocyte chemoattractant protein-1 gene therapy inhibits vascular remodeling in rats: blockade of MCP-1 activity after intramuscular transfer of a mutant gene inhibits vascular remodeling induced by chronic blockade of NO synthesis

Monocyte chemoattractant protein-1 (MCP-1) may play an essential part in the formation of arteriosclerosis by recruiting monocytes into the arterial wall. Thus, we devised a new strategy for anti-MCP-1 gene therapy against arteriosclerosis by transfecting an amino-terminal deletion mutant (missing the amino-terminal amino acids 2 to 8) of the human MCP-1 gene into a remote organ (skeletal muscles). Intramuscular transduction with the mutant MCP-1 gene blocked monocyte recruitment induced by a subcutaneous injection of recombinant MCP-1. In a rat model in which the chronic inhibition of endothelial nitric oxide synthesis induces early vascular inflammation as well as subsequent coronary vascular remodeling, this strategy suppressed monocyte recruitment into the coronary vessels and the development of vascular medial thickening, but did not reduce perivascular fibrosis. Thus, MCP-1 is necessary for the development of medial thickening but not for fibrosis in this model. This new strategy may be a useful and feasible gene therapy against arteriosclerosis.

Angiotensin-converting enzyme inhibitor inhibits dehydration-enhanced fever induced by endotoxin in rats

It has been reported that a host develops a marked fever under dehydrated conditions compared with normally hydrated conditions (11). The present study was carried out to investigate whether ANG II is involved in the enhancement seen in dehydrated rats of the fever induced by bacterial endotoxin. The results showed that intravenous injection of bacterial endotoxin produced a fever in dehydrated rats (rats deprived of water for 24 h) that was significantly greater than that seen in normally hydrated rats. In contrast, dehydration had no effect on the fever induced by intravenous interleukin-1beta (IL-1beta). Under dehydrated conditions, the enhanced endotoxin-induced fever was significantly inhibited by the angiotensin-converting enzyme inhibitor lisinopril, but the IL-1beta fever was not. These results suggest that the dehydration-induced enhancement of endotoxin fever is due, at least in part, to the action of ANG II, which elicits an increased production of pyrogenic cytokines such as IL-1.

Fibrosis and hypertensive heart disease

The normal myocardium is composed of a variety of cells: cardiac myocytes and noncardiomyocytes, which include endothelial and vascular smooth muscle cells and fibroblasts. Hypertensive heart disease involves a structural remodeling of muscular and nonmuscular compartments. It is not the quantity but rather the quality of myocardium that accounts for pathologic hypertrophy and predisposes to ventricular dysfunction and arrhythmias, which, in turn, confer increased risk of adverse cardiovascular events. Herein, factors regulating growth of these compartments are reviewed and in particular signals involved in promoting adverse remodeling of intramyocardial coronary arteries and arterioles by fibrous tissue.