Egg white protein hydrolysate reduces blood pressure, improves vascular relaxation and modifies aortic angiotensin II receptors expression in spontaneously hypertensive rats

Angiotensin converting enzyme (ACE) inhibitory peptides from egg have demonstrated reduction of blood pressure (BP) in vivo. In this study we evaluated the effects of egg white hydrolysate (EWH) prepared by thermolysin and pepsin in spontaneously hypertensive rats (SHRs). Fourteen to sixteen week old SHRs were implanted with telemetry devices. After recovery, the rats were divided randomly into three groups: untreated, EWH low dose (250 mg/kg BW), and EWH high dose (1000 mg/kg BW) for 12 days. BP showed a significant reduction in the EWH high dose group compared to untreated controls. BP reduction was associated with enhanced ex vivo vasodilation reduced oxidative/nitrosative stress, reduced angiotensin converting enzyme and angiotensin II type 1 receptor expression, while enhanced angiotensin II type 2 receptor expression. Circulating level of angiotensin II was unaffected. Thus, EWH exerted anti-hypertensive effects in SHRs through multiple mechanisms of vascular relaxation and RAS modulation.