The therapeutic potential of bradykinin B2 receptor agonists in the treatment of cardiovascular disease

The nonapepticle bradykinin (BK) is a Janus-faced hormone, which exerts pathophysiological as well as pronounced beneficial physiological effects, mainly by stimulation of BK B-2 receptors. In various animal models and in humans it has been shown that the stimulation of BK B2 receptors is not only implicated in the pathogenesis of inflammation, pain and tissue injury but also in powerful cardioprotective mechanisms. Either exogenous administration of BK or locally increased BK concentrations as a consequence of the inhibition of its metabolic breakdown by angiotensin-converting enzyme inhibitors, reveal the significant contribution of BK in powerful cardioprotective mechanisms. These are mainly triggered by the synthesis and release of the vasorelaxant antihypertrophic and antiartherosclerotic endothelial mediators nitric oxide, prostaglandins and tissue-type plasminogen activator, by ischaemic preconditioning and by an increase in insulin sensitivity. Consequently, BK B-2 receptor agonists may have important clinical value in the treatment and prevention of various cardiovascular disorders such as hypertension, ischaemic heart disease, left ventricular hypertrophy, ventricular remodelling and congestive heart failure as well as diabetic disorders by mimicking the reported beneficial effects of BK. However, none of the currently known potent and selective peptide and non-peptide agonists of BK B-2 receptors - RMP-7 (lobradamil, Cereport(R); Alkermes), JMV-1116 (Fournier), FR-190997 (Fujisawa) and FR-191413 (Fujisawa) - have been selected for a clinical assessment in cardiovascular indications. One major challenge of this approach is the still unanswered question of whether there is a sufficient safe therapeutic window between potential cardioprotective and pro-inflammatory effects following BK B2 receptor agonism.