Milk casein-derived tripeptides (Ile-Pro-Pro, Val- Pro-Pro and Leu-Pro-Pro) and functional food products containing them lower blood pressure in experimental models of hypertension (spontaneously hypertensive rats (SHR), salt-loaded Goto- Kakizaki rats, transgenic rats harboring human renin and angiotensinogen genes) (see, Jäkälä & Vapaatalo 2010) and in mildly hypertensive subjects (see, Turpeinen et. al. 2012) and improve vascular relaxation ex vivo and in vivo. The mechanism of their antihypertensive effect has been suggested to be related to ACE1- inhibition and thus reduced formation of the potent vasoconstrictor, angiotensin II (Ang II). However, ACE1 inhibition and lowering of blood pressure do not explain – at least alone - the improved endothelial function. We present here data from in vitro experiments which show that Ile-Pro-Pro pretreatment augments bradykinin- induced vasorelaxation. (Ehlers et. al. 2011) We also evaluate effects of MR antagonist A-779 and age of the rats on bradykinin-induced vasorelaxation. MR is a receptor for a vasodilatory component Ang(1–7) in renin angiotensin system (RAS). The presented novel hypotheses for mechanisms of improved endothelial function by the bioactive tripeptides remain to be confirmed in man.

References: 

Ehlers PI et. al. 2011. Life Sciences 88:206–211. Jäkälä P. & Vapaatalo H. 2010. Pharmaceuticals 3:251–272., Turpeinen AM et. al. 2012. Annals of Medicine: DOI:10.3109/07853890.2012.663926. Supported by: The Finnish Funding Agency for Technology and Innovations (TEKES)